1976 – June 5, Teton Dam Failure, Teton River, ~Newdale, Southeast Idaho –11-12

lornajarrettblanchard June 5, 1976

— 14 Delatte. Beyond Failure: Forensic Case Studies for Civil Engineers. 2009, p. 223.[1]

— 14 Indep. Panel. Report…Dept…Interior and… Idaho on Failure of Teton Dam. P.v., 1-1.[2]

–11-12 Blanchard tally. (Using official tally of 11[3] plus electrocution of repair workman.)[4]

— 11 ABC News. “The Johnstown Flood: the Worst Dam Failure in U.S. History.” 2007.

— 11 Carper and Feld. Construction Failure. 1997, p. 13.

— 11 Bureau of Reclamation, US Dept. of Interior Teton Dam History. 7-25-2016 update.[5]

— 11 Deseret News (Borrowman). “40^th anniversary of the collapse of the Teton Dam.” 6-3-2016.[6]

— 11 Idaho State Journal, Pocatello. “Robison and Captain of the USS Titanic…” 6-5-1977.[7]

— 11 Idaho Statesman. “40 years later, remembering Idaho’s Teton Dam collapse.” 6-5-2016.

— 11 Johnson. “Teton Dam Flood – June 5, 1976.” Fremont County, Idaho, GenWeb Project.

— 11 Maize. “Carter’s Water Policy Prepared” (Editorial). Daily News-Record, 6-5-1978, p6.[8]

— 11 OJP DOJ. Community Crisis Response Team Training Manual: 2^nd Ed. (Appendix D).).

— 11 Reisner. Cadillac Desert: The American West and its Disappearing Water. 1993, p.407.

— 11 US DHS. Dams Sector: Estimating Loss of Life for Dam Failure Scenarios. 2011, p. 75.

— 11 US Dept. Interior Teton Dam Failure Review Group. Failure of Teton Dam. 1977, p.42.[9]

— 11 USGS. Summary of Significant Floods in the US, PR, and the VI, 1970-1989. 2008.

— 11 US House Cmmte. on Science and Technology. Structural Failures in Public Facilities.

— 9 RoadsideAmerica.com. “Teton Flood Museum, Rexburg, Idaho.” 2016.[10]

Narrative Information

Bureau of Reclamation: “On June 5, 1976, Teton Dam in southeastern Idaho catastrophically failed. Early that Saturday morning, bulldozer operators tried in vain to plug seepage holes on the downstream face of the dam. By 11 a.m., a torrent of water ripped through the dam, releasing more than one million cubic feet per second. The communities of Sugar City, Rexburg, and Wilford were battered by the trees, houses, cattle and cars carried by the floodwaters. In the end, 11 people died and there was millions of dollars in property damage.

“Reclamation’s Dam Safety program evolved out of this disaster.

“….When Teton Dam failed, the reservoir was 270 feet deep (at the dam) and drained in less than six hours. The filling and the subsequent rapid draining of the reservoir triggered more than 200 landslides in the river canyon that was inundated by the former reservoir….” (Bureau of Reclamation, US Dept. of Int. Teton Dam History (webpage). 7-25-2016 update.)

Carper and Feld: “Teton Dam, Idaho, June 1976. Failure of a 93-m (305-ft)-high dam cost over $1 billion in property losses, loss of 11 lives, and over 2000 injuries.” (Carper and Feld. Construction Failure. 1997, p. 13.)

DHS: “Teton Dam was located in southeastern Idaho, approximately 39 air miles northeast of Idaho Falls. The earthfill dam, undergoing initial filling, was constructed to provide water for irrigation purposes.

“The dam failed at 11:57 am on Saturday, June 5, 1976. At the time of failure, the sky was sunny or partly cloudy and the air temperature was 81º F. The dam was being filled for the first time when failure occurred as a result of piping of the dam core in the foundation key trench.

“Teton Dam had a height of 305 feet, although at the time of failure the water level in the reservoir was 30 feet below the dam crest. The reservoir volume at the time of failure was approximately 250,000 acre-feet. The drainage area upstream of the dam was 840 square miles.

“Teton Dam was unattended from 12:30 am until 7:00 am on the day of the failure. Between 7:00 am and 8:00 am, survey crew members discovered turbid leakage. At 9:30 am, the Project Construction Engineer considered alerting residents but did not issue an alert. He determined that an emergency situation was not imminent and he was concerned about causing undue panic. At 10 am, a larger leak was discovered with flowing turbid water. Between 10:30 am and 10:45 am the Project Construction Engineer notified the sheriff’s offices and advised them to alert citizens.

“Warnings were initiated a little more than an hour before dam failure. Warnings were issued by police and further spread by commercial radio and television as well as neighborly word of mouth and telephone. Live radio broadcasts had reporters at the dam and in fixed wing aircraft flying above the dam and above downstream communities. The daytime failure combined with clear weather resulted in many people obtaining an important visual cue – the sight of the dust cloud and debris near the leading edge of the flood wave. Most people were able to evacuate before the house-destroying flood water arrived.

“The flood varied in intensity as it traveled 156 miles from Teton Dam to American Falls Reservoir. The flooding was much more severe near Teton Dam than it was farther downstream of the dam. Water depths ranged from approximately 75 feet near the dam to 50 feet near the mouth of the five-mile-long Teton River canyon, with velocities possibly exceeding 40 feet per second. The communities of Wilford and Sugar City (12.3 miles from the dam) were flooded by a 15-foot “wall of water” at approximately 1:00 pm The leading edge of the flood wave struck Rexburg (mile 15.3) about 1:40 pm and within minutes approximately 80 percent of the city was inundated to depths of 6 to 8 feet. Flooding began in Roberts (mile 43) approximately 9 hours after the initial failure and reached depths of 5 to 6 feet. Floodwaters reached Idaho Falls (mile 63) 13 hours after failure, but only minor flooding occurred because sandbag levees were erected. Flooding began at the Snake River near the Shelley U.S. Geological Survey (USGS) gauging station (mile 71) approximately 14 hours after failure. River levels then rose from 0.5 to 1.5 feet per hour for the next 21 hours until the peak discharge of 67,300 cubic feet per second was recorded….

“Floodwaters reached American Falls Reservoir (mile 156) at 12:30 am on June 7, approximately 36 hours after the failure of Teton Dam. The flood eventually covered between 150 and 200 square miles; flooding was several miles wide in some places.

“The flooding destroyed or damaged more than 3,700 houses. There were approximately 25,000 people at risk. There were 11 fatalities and 800 injuries (including those from after-flood cleanup). There were six deaths from drowning, three from heart failure, one from accidental gunshot, and one from a self-inflicted gunshot. Ten of the eleven people who died had been warned of the impending flooding. The unwarned person who died was fishing off a small island in the Teton River when water began to rise. He and a fishing partner tried to swim to safety, but only his partner survived…. The dam has not been rebuilt.” (US DHS. “Teton Dam, Idaho – Failed in 1976,” pp. 74-75 in: Dams Sector: Estimating Loss of Life for Dam Failure Scenarios. Sep 2011.)

Graham: “…the highest dam that has ever failed in the United States.” (Graham, Bureau of Reclamation, 1999)

Independent Panel: “The Independent Panel to Review Cause of Teton Dam Failure has completed its task, as charged by the Secretary of the United States Department of the Interior and the Governor of the State of Idaho in letters from Secretary Kleppe, dated June 11, 23, and 30, 1976. The Panel submits its report herewith. These pages present a summary and conclusions.

“Teton Dam failed on June 5, 1976, when the reservoir was at El. 5301.7, 3.3_ ft below the spillway sill. Although downstream warnings are believed to have been timely, deaths of 14 persons and property damage estimated variously from 400 million to one billion dollars have been attributed to the failure.

“Construction of Teton Dam was authorized on September 7, 1964, by Public Law 88-583. The dam is situated on the Teton River, three miles northeast of Newdale, Idaho. Prior to 1963, the proposed dam was known as Fremont Dam.

“Teton Dam and its reservoir were principal features of the Teton Basin Project, a multipurpose project embodying flood control, power generation, and supplemental irrigation water supply. The dam was a central-core zoned earthfill structure, with a height of 305 ft above the riverbed and 405 ft above the lowest point in the foundation. Provisions for seepage control included a key trench in the foundation rock above El. 5100 and a cutoff trench to foundation rock below that elevation. A grout curtain extended below these trenches…. [p. vi.]

“The Panel’s conclusions are summarized below:

The records show that the pre-design site selection and geological studies were appropriate and extensive. The pilot grouting program carried out in 1969 forecast the difficulties to be experienced in construction of the final grout curtain.

The design followed USBR practices, developed over a period of many years from experience with other Bureau projects, but without sufficient consideration of the effects of differing and unusually difficult geological conditions at the Teton Damsite. Every embankment can be said to have its own personality requiring individual design consideration and construction treatment. Treatment of such individualities produces most of the continuing advances in dam design and construction technology.

The volcanic rocks at the Teton Damsite are highly permeable and moderately to intensely jointed. Water was therefore free to move with almost equal ease in most directions, except locally where the joints had been effectively grouted. Thus during reservoir filling, water was able to move rapidly to the foundation of the dam. Open joints existed in the upstream and downstream faces of the right abutment key trench, providing potential conduits for ingress or egress of water.

The wind-deposited nonplastic to slightly plastic clayey silts used for the core and key trench fill are highly erodible. The Panel considers that the use of this material adjacent to the heavily jointed rock of the abutment was a major factor contributing to the failure.

Construction of the project was carried out by competent contractors under formal contracts administered in accord with well-accepted practices. Controversy between the contractors and Bureau of Reclamation officials which might have affected the quality of the work seems not to have occurred. Construction activities conformed to the actual design in all significant aspects except scheduling.

One construction condition which affected the Bureau’s ability to control the rate of filling of the reservoir was the delay that occurred in completion of the river outlet works. However, the Panel believes that the conditions which caused the piping and consequent failure of the dam were not materially affected by the fact that the reservoir was filled at a more rapid rate than had been originally planned. A slower rate of filling would have delayed the failure but, in the judgment of the Panel, a similar failure would have occurred at some later date.

The records show that great effort was devoted to constructing a grout curtain of high quality, and the Panel considers that the resulting curtain was not inferior to many that have been considered acceptable on other projects. Nevertheless, the Panel’s on-site tests and other field investigations showed that the rock immediately under the grout cap, at least in the vicinity of Stas. 13+00 to 15+00, was not adequately sealed, and that additional unsealed openings may have existed at depth in the same locality. The leakage beneath the grout cap was capable of initiating piping in the key trench fill, leading to the formation of an erosion tunnel across the base of the fill. The Panel considers that too much was expected of the grout curtain, and that the design should have provided measures to render the inevitable leakage harmless.

The geometry of the key trenches, with their steep sides, was influential in causing transverse arching that reduced the stresses in the fill near the base of the trenches and favored the development of cracks that would open channels through the erodible fill. Arching in. the longitudinal direction, due to irregularities in the base of the key trenches, and arching adjacent to minor irregularities and overhangs, undoubtedly added to the reduction of stress.

Stress calculations by the finite element method indicated that, at the base .of the key trench near Stas. 14+00 and 15+00, the arching was great enough that the water pressure could have exceeded the sum of the lateral stresses in the impervious fill and the tensile strength of the fill material. Thus, cracking by hydraulic fracturing was a theoretical possibility and may have led to flow of water in the base of the key trench between Stas. 14+00 and 15+00, and erosion of the key trench fill.

Close examination of the interior of the auxiliary outlet tunnel showed no distress of any kind such as would be expected had the right abutment, through which the tunnel passes, been subjected to significant settlement or other structural change. Geodetic resurveys showed only minor surface movements as a result of reservoir filling and emptying. Accordingly, differential movements of the foundation are not considered to have contributed to the failure.

The Panel found no evidence that seismicity was a factor in failure of the dam.

The dam and its foundations were not instrumented sufficiently to enable the Project Construction Engineer and his forces to be informed fully of the changing conditions in the embankment and its abutments.

Following its first working session, the Panel reported that it then seemed apparent that the failure resulted from piping, a process by which embankment material is eroded internally and transported by water flowing through some channel in the embankment section. That conclusion remains valid. The Panel’s investigations since that time have been directed particularly to determining the most probable manner in which such piping erosion started. The Panel believes that two mechanisms are suspect. Either could have worked alone or both could have worked together. One is the flow of water against the highly erodible and unprotected key trench filling, through joints in the unsealed rock immediately beneath the grout cap near Sta. 14+00 and the consequent development of an erosion tunnel across the base of the key trench fill. The other is cracking caused by differential strains or hydraulic fracturing of the core material filling the key trench. This cracking would also result in channels through the key trench fill which would permit rapid internal erosion.

In either case, leakage occurring through the key trench ultimately initiated further erosion along the downstream contact of the core and the abutment rock. Since the core material was both easily erodible and strong, any erosion channels in the core, along the contact with the rock, readily developed into large tunnels or pipes before becoming visible along the downstream parts of the dam.

It should be noted that this description of the failure mechanism does not provide a final answer to the specific cause of failure of Teton Dam. Clearly many aspects of the site and the embankment design contributed to the failure, but because the failed section was carried away by the flood waters, it will probably never be possible to resolve whether the primary cause of leakage in the vicinity of Sta. 14+00 was due to imperfect grouting of the rock below the grout cap, or cracking in the key trench fill, or possibly both. There is evidence to support both points of view. Nevertheless, while the specific cause may be impossible to establish, the narrowing of the possibilities to these two aspects of design and construction is likely to serve as an important but tragic lesson in the design and construction of future projects of this type.

The fundamental cause of failure may be regarded as a combination of geological factors and design decisions that, taken together, permitted the failure to develop. The principal geologic factors were (1) the numerous open joints in the abutment rocks, and (2) the scarcity of more suitable materials for the impervious zone of the dam than the highly erodible and brittle windblown soils. The design decisions included among others (1) complete dependence for seepage control on a combination of deep key trenches filled with windblown soils and a grout curtain; (2) selection of a geometrical configuration for the key trench that encouraged arching, cracking and hydraulic fracturing in the brittle and erodible backfill; (3) reliance on special compaction of the impervious materials as the only protection against piping and erosion of the material along and into the open joints, except some of the widest joints on the face of the abutments downstream of the key trench where concrete infilling was used; and (4) inadequate provisions for collection and safe discharge of seepage or leakage which inevitably would occur through the foundation rock and cutoff systems.

The difficult conditions of the site called for basing the design on the most unfavorable assumptions compatible with the geologic conditions concerning the behavior of the water and its possible effect on the embankment. Instead of placing so much dependence on the key trenches and grout curtain, measures should have been developed to render harmless whatever water did pass, irrespective of the reasons.

In final summary, under difficult conditions that called for the best judgment and experience of the engineering profession, an unfortunate choice of design measures together with less than conventional precautions was taken to ensure the adequate functioning of the Teton Dam, and these circumstances ultimately led to its failure.” (pp. vii-ix.)

“The dam failed on June 5, 1976, when the reservoir water level was at E.. 5301.7. That level was 22.6 ft below the maximum water level and 3.3 ft below the spillway sill.

“The inundation downstream was disastrous, and the loss of the lives of 14 persons has been associated directly or indirectly with the failure. Property damage has been estimated at various amounts from $1 billion downward. The current best estimate seems to be $400 million.” (p 1-1.)

(Independent Panel to Review Cause of Teton Dam Failure. Report to U.S. Department of the Interior and State of Idaho on Failure of Teton Dam. Idaho Falls, ID. Dec 1976.)

Johnson: “Official death toll [11] from the Teton Dam Flood:

Daw, Clarence, 79, Wilford, died June 5 when unable to escape flood waters as they hit his home. Warned by grandson to leave when word received there was a leak in the dam. Apparently never knew the dam broke until it was too late.
Daw, Florence, 76, wife of Clarence Daw.
Bedford, Glen, 30, Parker, was trying to help remove household items from wife’s parents’ home in Wilford. Died June 5.
Bedford, James, 33, Parker, with Glen Bedford June 5.
Benson, David J., 21, Teton, drowned when hit by the wall of water while fishing on the Teton River just below the dam June 5.
Gillette, Mary Jones, 94, oldest resident of Teton City, died June 6 at a Driggs hospital after being evacuated from the flood area.
Heyrend, John W., 72, Idaho Falls, died of a heart attack while loading valuables and emergency supplies into his car in anticipation of an order of evacuation, June 5.
McRae, Charles, 55, Parker, went with Glen and James Bedford. Drowned June 5.
Pendrey, Natalee, 62, Rexburg, died of a heart attack June 6. Had a previous heart condition, evacuation contributed to death.
Peterson, Stanley E., 51, Rexburg, died June 5 of an accidental gunshot wound sustained when removing a gun from his vehicle.
Virgin, Karen Ann Ottesen, 29, St. Anthony, died June 10 near her home of a self-inflicted gunshot wound. Authorities attributed her death to psychological problems concerning the Teton Dam flood.

(Johnson, Elaine. “Teton Dam Flood – June 5, 1976.” Fremont County, Idaho, GenWeb Project.)

OJP: 1,014 homes Destroyed, 2,620 homes severely damaged. (OJPDOJ. CCRTTM: Ed. 2 Append D)

USGS: “The greatest flood disaster of 1976 occurred on June 5 when the Teton Dam in Idaho failed. The Teton Dam is located on the Teton River in the headwaters of the Snake River Basin. The dam was breached as the reservoir was filling for the first time. About 173,000 acre-ft of water drained through the dam in 2 hours and 23 minutes. The maximum discharge downstream from the dam was estimated at 2.3 million ft³/s. The flood caused 11 deaths, and damages were estimated at $400 million (Paulson and others, 1991[11]).” (USGS. Summary of Significant Floods in the US, PR, and the VI, 1970-1989. 2008.)

Newspapers

June 6: “The recently completed Teton Dam burst Saturday [June 5] morning, sending a 15 foot tall torrent of water rushing down the Teton River and forcing the evacuation of over 15,000 persons living in communities along the Snake River. No fatalities had been reported by Saturday night, although property damage in Sugar City, Rexburg, Rigby, St. Anthony, Idaho Falls and numerous communities along the Snake River was expected to run into millions of dollars. Reports from Idaho State Journal photographers flying over the area indicated that as much as 25 to 30 square miles of land might be under water….According to the Idaho State Police, the wall of water was as wide as five miles at some points and shooting down the Teton River at a speed of a mile every five minutes. Evacuation of Sugar City, Rexburg and parts of Idaho Falls began immediately after the structure collapsed.

“One eyewitness said that only several hundred cattle, out of 6,000 that were in the Meyers Brothers Feed Lot north of Sugar City, were able to scramble out of the way of the 15-foot-tall torrent of water that hit that tiny farming town.

“Idaho Gov. Cecil D. Andrus early Saturday afternoon declared a state of extreme emergency for the state of Idaho and directed the National Guard to mobilize ‘all the facilities and manpower services that can be made available.’ Andrus flew over the flooded Southeast Idaho area Saturday afternoon and issued a statement saying he was ‘overwhelmed’ at the destruction. ‘Part of Sugar City is there, and part of it is just gone,’ Andrus said. After touring the disaster-stricken area Andrus sent a telegram to President Ford, requesting the immediate declaration of a disaster area. ‘I have personally viewed the destruction and am overwhelmed by the size and scope of the disaster,’ Andrus telegraphed Ford. ‘Entire towns are inundated or washed away in part. Please instruct the federal agencies to move into the area immediately.’

“Construction of the $55 million earth-filled structure was topped out last December, though work on some parts of the project was still under way….The day was 310 feet tall, stretched 3,000 feet at the crest and was 35 feet wide at the top….” (Idaho Journal, Pocatello, ID. “New Teton Dam Bursts, 15,000 Flee. No Fatalities Logged; Property Damage High.” 6-6-1976, p. 1.)

June 7: “….The first confirmed death from the flood [of six reported] is David Benson, 21, of Teton, who was fishing when the waters struck….” (Idaho State Journal/AP. “Flood Crest Hits Blackfoot; Death Toll, Losses Mount.” 6-7-1976, p. 1.)

June 8: “Newdale, Idaho (AP) — The formal Bureau of Reclamation report from the project engineer at the Teton Dam detailed in simple terms the beginning of the biggest disaster ever to strike Idaho. Robert R. Robison prepared a short, formal letter to officials of the bureau, telling of the few frantic hours before the dam burst Saturday. His report:

Notice of major leaks were first given at 8:30 a.m. June 5. One leak was at approximate elevation 5200 at the junction of the dam embankment and the right side abutment was flowing at about two cubic feet per second, slightly turbid. The second leak was at the downstream toe of the dam at the right abutment elevation 5045 and was flowing at about 50 cubic feet per second and was issuing at the abutment rock, moderately turbid.

U.S. Bureau of Reclamation representatives directed contractor Morrison-Knudsen-Kicwil to begin work immediately with dozers on the right abutment of the dam on the down-stream side to fill openings with large rock, and channel the flow of water to the tailrace (downstream below the dam).

U.S. Bureau of Reclamation officials were notified about 9:45 a.m. The sheriff’s offices in Madison and Fremont counties were notified by 10 a.m. to alert citizens for potential flooding from Teton dam and be prepared to evacuate the area downstream.

At about 10 a.m., a large leak developed about 15 feet from the right abutment in the dam embankment in the dam embankment at approximate elevation 5200, which first flowed at 15 cubic feet per second.

At 11 a.m. a whirlpool developed on the upstream side of the dam, at approximate elevation 5295. Gibbons and Reed contractor dozers arrived at 11 a.m. and were directed to begin dozing zone 2 and riprap material into the whirlpool area.

The hole in the downstream face of the embankment increased in size and flow and remedial work at this location was stopped at 11:30 a.m. when two dozers were lost in the opening.

Additional notification was given to both Madison and Fremont county sheriff’s offices between 11 a.m. and 11:30 a.m. to evacuate areas below the dam.

At 11:57 a.m. the dam was breached and a tremendous wall of water surged through the opening in the dam. Telephone and power service was cut off at this time.

Reservoir water surface at 8:30 a.m. June 5 was at elevation 5301 (feet). At 2 p.m. this date, it had lowered to elevation 5217. At 2:20 p.m. the reservoir water surface was at elevation 5179. At 3:55 p.m. the reservoir water surface was at elevation 5110 and at 5 p.m., the reservoir water surface was at 5085. At about 8 p.m., the reservoir had drained to approximate elevation 5080 and flow was nearly stabilized at normal flood flow.

The channel downstream from the dam is filled to at least 30 feet in depth for a considerable distance downstream. About 40 per cent of the dam embankment has been lost. The powerhouse and warehouse structure are completely submerged in debris.’”

(Idaho State Journal, Pocatello. “Report Details Disaster.” 6-8-1976, B1.)

June 9: “Drowning, exposure, heart failure, shock and an accidental shooting caused the deaths of nine known victims of the Teton Dam flood. Names of the victims were officially released Tuesday night. They are: Clarence and Florence Daw, Wilford, Idaho; Mary Gillette, Teton City; James C. Bedford and Charles McRae, both of Parker; David Benson, Teton; Stanley E. Peterson, Rexburg; Jack Heyrend, Idaho Falls, and Natalee Pendrey, Rexburg.

“Paul Romrell, Fremont County coroner and administrator at Fremont General Hospital, described the circumstances surrounding six of the victims’ deaths.

“Clarence Daw, 79, and his wife Florence, age unknown, were found dead in their pickup truck, which apparently was washed about a mile and a half away from their home. The ignition switch was on when they were discovered. Cause of their deaths is attributed to drowning. The Daws were either driving or attempting to drive away from their home, which was located at the entrance of a canyon hard hit by the Teton Dam waters….

“Mary Gillette, 94, was an invalid who lived in Teton City. When news of the flood’s imminent arrival came, she was evacuated from her home. She became ill after spending several hours out of doors and was transferred to Driggs. ‘It’s my opinion she would bot be dead today if she hadn’t been evacuated and exposed,’ Romrell said.

“James C. Bedford, 33, and Charles McRae, 56, were swept away by flood waters while assisting in the evacuation of furniture from a Wilford home. McRae’s body was later found in Madison County. His brother, who just moved to the town from Colorado, is still missing and is presumed drowned….

“The body of David Benson, 21, was found near an overpass north of Sugar City. He and Daryl Griggs of St. Anthony were fishing along the Teton River when the dam’s waters cascaded down upon them. Griggs is listed in serious condition at an Idaho Falls hospital. The body of a third fishing party member has yet to be found.

“Stanley Peterson, 51, accidentally shot himself while protecting his Rexburg home, a spokesman for Idaho Falls hospital said.

“The hospital spokesman said Jack Heyrend, 72, died of heart failure Saturday afternoon when trying to prepare his Idaho Falls home for flood waters.

“Natalee Pendrey, 62, is the ninth known victim. She died of a heart attack in Rexburg….”

(Idaho State Journal, Pocatello. “Here’s How Nine Flood Victims Died.” 6-9-1976, p. 1.)

June 10: “….Two residents from Teton were among the 10 reported flood fatalities. Mary Gillette, 94, was an invalid who lived in Teton. When news of the dam’s break came, she was evacuated from her home. After several hours out of doors she became ill and died. ‘It’s my opinion she would not be dead today if she hadn’t been evacuated and exposed,’ said Paul Romrell, Fremont County coroner and administrator at Fremont General Hospital.

“David Benson, 21, was another Teton resident killed by the flooding. He and Daryl Griggs of St. Anthony were fishing along the Teton River when a 20-foot wall of water washed them down the canyon. A third fishing companion has not yet been found….

“Two flood-related deaths in Rexburg have been reported. Stanley Peterson, 51, accidentally shot himself while protecting his Rexburg home, a spokesman for the Idaho Falls hospital said. Natalie Pendry, 62, died of a heart attack in Rexburg….’ (Idaho State Journal, Pocatello. “Seven Idaho Communities Dig Out from Teton Flood.” 6-10-1976, 2A.)

June 11: “Idaho Falls, Idaho (UPI)….Deaths related to the disaster…climbed to 10 — five of them by drowning — when a St. Anthony woman shot herself. Between 40 and 60 persons still were reported missing. The number of injuries, many of them cuts resulting from home repairs and cleanup, jumped to 2,255. Only 10 of these persons were hospitalized. One was in critical condition from a heart attack and another was listed in serious condition….” (Times-News, Twin Falls, ID. “200 mobile homes taken to Teton disaster area.” 6-11-1976, p. 3.)

June 12: “Federal relief efforts for the victims of the Teton Dam disaster moved into high gear Friday when President Ford sent to Congress an emergency appropriations request of $200 million for special payments to Idahoans who lost their homes, crops and livestock….Ten confirmed flood-related deaths have been reported….” (Salt Lake Tribune, UT. “Ford Asks $200 Million for Idaho Aid.” 6-12-1976, p. 1.)

June 13: “Idaho Falls, Idaho (AP) — One week after the collapse of the Teton Dam, relief agencies narrowed to eight the number of persons believed missing. Ten persons have been confirmed dead….” (Idaho Sunday Journal, Pocatello. “Latest Casualty List: 10 Dead, 1 Missing.” 6-13-1976, p. 1.)

June 14: “Denver (AP) — Opposition from environmentalists and officials within his own department almost caused former Interior Secretary Rogers C.B. Morton to kill the Teton Dam proposal, it was reported Sunday [June 13]. The Teton Dam in Southeast Idaho collapsed June 5, killing at least 10 persons and causing more than $1 billion in damages…. The Rocky Mountain News reported that Morton, now President Ford’s campaign manager, was convinced at one point in 1971 that the project offered marginal economic benefits.

“Project opponents within the department were also worried about environmental problems the Teton Dam would cause… R.P. Van Gytenbeek, the former Trout Unlimited national director who battled the project, said Morton told him in 1971 that while he sympathized with environmentalists, politics led to the dam’s approval. ‘He pointed out the political realities of trying to stop a project when both senators from a state were for it,’ said the newspaper quoted Van Gytenbeek as saying. Idaho’s senators at the time were Frank Church, a Democrat, and Len Jordan, a Republican who’s now retire. Morton told the Rocky Mountain News in a telephone interview the issue was a ‘close call’ and ‘we stiff-armed it for a while.’ But hew said he didn’t think the project was ever really killed.” (Idaho State Journal, Pocatello. “Teton Dam Once Nearly Cancelled.” 6-14-1976, p. B1.)

June 15: “Rexburg, Idaho (AP)….Twelve persons have been arrested for investigation of looting since Rexburg was flooded by the collapse of the Teton Dam, the police chief said….

“Ten persons were confirmed dead…including five drowning victims, three heart attack victims, a suicide and a Rexburg man who accidentally shot himself while preparing to guard his property from possible looters….

“Walter Joe Dealy, 47, of the Boise area was electrocuted Monday [June 14], his first day on the job, while driving a truck across a field on canal flood repair north of Idaho Falls. The truck hit a power line and he jumped out, but kept hold of the vehicle and suffered severe burns and heart failure, paramedics said….”[12] (AP. “Dozen Arrested For Post-Flood Looting.” Idaho State Journal, Pocatello, 6-15-1976, p. 9.)

June 20: “Boise, Idaho (AP) — No decision has been made whether to rebuild Teton Dam or relocate it elsewhere, a U.S. Bureau of Reclamation official said today….Teton Dam burst June 5, resulting in a flood which claimed 11 lives….” (Idaho State Journal, Pocatello. “No Decision Made on Teton Dam.” 6-20-1976, p. D1.)

Sources

ABC News (Connie Clarke). “The Johnstown Flood: the Worst Dam Failure in U.S. History — The Kaloko Dam Disaster Has Many Antecedents.” 3-2-2007. Accessed 1-28-2017 at: http://abcnews.go.com/2020/story?id=2918360&page=1

Associated Press. “Dozen Arrested For Post-Flood Looting.” Idaho State Journal, Pocatello, 6-15-1976, p. 9. Accessed 1-28-2017 at: http://newspaperarchive.com/us/idaho/pocatello/idaho-state-journal/1976/06-15/page-9?tag

Bureau of Reclamation, U.S .Department of the Interior. Teton Dam History (webpage). 7-25-2016 update. Accessed 1-28-2017 at: https://www.usbr.gov/pn/snakeriver/dams/uppersnake/teton/index.html

Carper, Kenneth L. and Jacob Feld. Construction Failure. John Wiley & Sons, Inc., 1997. Partially digitized by Google at: http://books.google.com/books?id=-jnlb-oJxcEC&printsec=frontcover&source=gbs_v2_summary_r&cad=0#v=onepage&q=&f=true

Delatte, Norbert J. Jr. Beyond Failure: Forensic Case Studies for Civil Engineers. Reston, VA: American Society of Civil Engineers Press, 2009.

Deseret News (Jerry Borrowman), Salt Lake City, UT. “40^th anniversary of the collapse of the Teton Dam.” 6-3-2016. Accessed 1-29-2017 at: http://www.deseretnews.com/article/865655585/40th-anniversary-of-the-collapse-of-the-Teton-Dam.html

Find A Grave. “Walter Joe Dealy.” Record created by Sheryl and added 1-17-2011. Accessed 1-30-2017 at: https://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GSln=Dealy&GSiman=1&GSst=15&GRid=64309884&

Idaho State Journal/Associated Press. “Flood Crest Hits Blackfoot; Death Toll, Losses Mount.” 6-7-1976, p. 1. Accessed 1-28-2017 at: http://newspaperarchive.com/us/idaho/pocatello/idaho-state-journal/1976/06-07?tag

Idaho State Journal, Pocatello. “Here’s How Nine Flood Victims Died.” 6-9-1976, p. 1. Accessed 1-29-2017 at: http://newspaperarchive.com/us/idaho/pocatello/idaho-state-journal/1976/06-09?tag

Idaho State Journal, Pocatello. “No Decision Made on Teton Dam.” 6-20-1976, p. D1. Accessed 1-29-2017 at: http://newspaperarchive.com/us/idaho/pocatello/idaho-state-journal/1976/06-20/page-35?tag

Idaho State Journal, Pocatello. “Report Details Disaster.” 6-8-1976, B1. Accessed 1-29-2017 at: http://newspaperarchive.com/us/idaho/pocatello/idaho-state-journal/1976/06-08/page-13?tag

Idaho State Journal, Pocatello. “Robison and Captain of the USS Titanic…” 6-5-1977, p. A7. Accessed 1-30-2017 at: http://newspaperarchive.com/us/idaho/pocatello/idaho-state-journal/1977/06-05/page-6?tag=

Idaho State Journal, Pocatello. “Seven Idaho Communities Dig Out from Teton Flood.” 6-10-1976, 2A. Accessed 1-28-2017 at: http://newspaperarchive.com/us/idaho/pocatello/idaho-state-journal/1976/06-10/page-2?tag

Idaho State Journal, Pocatello. “Teton Dam Once Nearly Cancelled.” 6-14-1976, p. B1. Accessed 1-29-2017 at: http://newspaperarchive.com/us/idaho/pocatello/idaho-state-journal/1976/06-14/page-11?tag

Idaho Statesman (Luke Ramseth and Bryan Clark, Post Register, Idaho Falls). “40 years later, remembering Idaho’s Teton Dam collapse.” 6-5-2016. Accessed 1-29-2017 at: http://www.idahostatesman.com/news/state/idaho/article81898907.html

Idaho Sunday Journal, Pocatello. “Latest Casualty List: 10 Dead, 1 Missing.” 6-13-1976, p. 1. Accessed 1-29-2017 at: http://newspaperarchive.com/us/idaho/pocatello/idaho-state-journal/1976/06-13?tag

Idaho Sunday Journal, Pocatello, ID. “New Teton Dam Bursts, 15,000 Flee. No Fatalities Logged; Property Damage High.” 6-6-1976, p. 1. Accessed 1-29-2017 at: http://newspaperarchive.com/us/idaho/pocatello/idaho-state-journal/1976/06-06?tag

Independent Panel to Review Cause of Teton Dam Failure. Report to U.S. Department of the Interior and State of Idaho on Failure of Teton Dam. Idaho Falls, ID. U.S. Government Printing Office, Washington, DC. December 1976, 590 pages. Accessed 1-28-2017 at: https://www.usbr.gov/pn/snakeriver/dams/uppersnake/teton/1976failure.pdf

Johnson, Elaine. “Teton Dam Flood – June 5, 1976.” Fremont County, Idaho, GenWeb Project. Accessed 1-29-2017 at: http://www.fremont.idgenweb.org/history-flood.html

Maize, Kennedy P. “Carter’s Water Policy Prepared” (Editorial). Daily News-Record, Harrisonburg, VA, 6-5-1978, p 6. Accessed 1-30-2017 at: http://newspaperarchive.com/us/virginia/harrisonburg/harrisonburg-daily-news-record/1978/06-05/page-6?tag

Office of Justice Programs, United States Department of Justice. Community Crisis Response Team Training Manual: Second Edition (Appendix D: Catastrophes Used as Reference Points in Training Curricula). Washington, DC: OJP, U.S. Department of Justice. Accessed at: http://www.ojp.usdoj.gov/ovc/publications/infores/crt/pdftxt/appendd.txt

Reisner, Marc. Cadillac Desert: The American West and its Disappearing Water (Revised and updated). NY: Penguin Books, 1993. Google digital preview accessed 1-29-2017 at: https://books.google.com/books?id=frvKDY0rpToC&printsec=frontcover#v=onepage&q&f=false

RoadsideAmerica.com. “Teton Flood Museum, Rexburg, Idaho.” 2016. Accessed 1-30-2017 at: http://www.roadsideamerica.com/story/2957

Salt Lake Tribune, UT. “Ford Asks $200 Million for Idaho Aid.” 6-12-1976, p. 1. Accessed 1-29-2017 at: http://newspaperarchive.com/us/utah/salt-lake-city/salt-lake-tribune/1976/06-12?tag

Stein, Eric A. The Teton Basin Project (Second Draft), Bureau of Reclamation History Program, Denver, Colorado, Research on Historic Reclamation Projects, 1996. Accessed 1-29-2017 at: https://web.archive.org/web/20080326232737/http://www.usbr.gov/dataweb/html/teton.html#N_2_

Times-News, Twin Falls, ID. “200 mobile homes taken to Teton disaster area.” 6-11-1976, p. 3. Accessed 1-28-2017 at: http://newspaperarchive.com/us/idaho/twin-falls/twin-falls-times-news/1976/06-11/page-3?tag

United States Department of Homeland Security. Dams Sector: Estimating Loss of Life for Dam Failure Scenarios. September 2011, 94 pages. Accessed 12-2-2017 at: https://www.hsdl.org/?view&did=726315

United States Department of the Interior Teton Dam Failure Review Group (Dennis N. Sachs and F. William Eikenberry, Chairmen). Failure of Teton Dam: A Report of Findings. Washington, DC: U.S. Government Printing Office, April 1977. Accessed 1-30-2017 at: https://archive.org/stream/failureoftetonda00teto#page/n59/mode/2up

United States Geological Survey. Summary of Significant Floods in the United States, Puerto Rico, and the Virgin Islands, 1970 Through 1989 (Water-Supply Paper 2502). USGS Kansas Water Science Center, Sep 17, 2008. Accessed 11-12-2016 at: http://ks.water.usgs.gov/pubs/reports/wsp.2502.contents.html#HDR1

United States House of Representatives, Committee on Science and Technology. Structural Failures in Public Facilities (Report by the Committee on Science and Technology together with Minority Views). Washington, DC: U.S. Government Printing Office, 1984. Accessed 1-28-2017 at: http://www.barrylepatner.com/documents/structuralfailures.pdf

[1] Presumably Delatte’s fatality figure is from the Independent Panel report to the Department of the Interior. We highlight in yellow to denote we are not using for our fatality range, in that it is not substantiated.

[2] Though the 590-page Independent Panel report twice notes 14 deaths reported as attributable to the dam failure, there is no other information on any of these deaths. Through review of other sources it appears to us that there were no more than twelve, and we are uncertain of the twelfth — the electrocution death.

[3] These are six drownings, one illness related to evacuation and exposure, two heart attacks, one accidental self-inflicted shooting, and one suicide due to self-inflicted gunshot wound.

[4] In a dam failure related news article at the time it is noted: “Walter Joe Dealy, 47, of the Boise area was electrocuted Monday, his first day on the job, while driving a truck across a field on canal flood repair north of Idaho Falls.” (AP. “Dozen Arrested For Post-Flood Looting.” Idaho State Journal, Pocatello, 6-15-1976, p. 9.) Given the wording of his death and in that it is an article related to the dam failure, it seems that this is a recovery-phase dam failure related death. This explains our range of the range of 11-12 (11 official, and 1 during repair and recovery, which was possibly dam failure related).

[5] Also from the Bureau: Eric A. Stein. The Teton Basin Project (Second Draft), 1996. In addition to noting 11 deaths, provides following detail in footnote 2: “Six of the victims died by drowning and two died of heart attacks. One victim was a ninety-four year old woman who was the oldest resident of Teton City. She died on June 6, 1976, in a hospital after being evacuated from the flood area. A twenty-nine year old woman died of a self-inflicted gunshot wound. Her psychological condition was blamed on the Teton flood. Another victim died of an accidental gunshot wound while removing a gun from his vehicle.” (Bureau of Reclamation. Annual Project History, Teton Basis Project, 1976-82, Record Group 115, 10-11.)

[6] “….Tragically, 11 people died along with 13,000 head of livestock. But with more than 100,000 people in the path of the water, it was something of a miracle that more lives weren’t lost. Although Idaho Falls, Idaho, and Blackfoot, Idaho, suffered severe damage, the American Falls reservoir finally contained the flood…”

[7] This one-year retrospective article on the failure, its ill-designed root cause, and the fate of the project construction engineer, notes that the failure “killed 11 people and caused $500 million in damage…”

[8] References the upcoming 2^nd anniversary of the collapse of the dam and the deaths of 11 people.

[9] “The tragic consequence was the loss of eleven lives and the disrupted lives of the 25,000 people who were left homeless as a result of the flooding.”

[10] “Lots of …black and white photos and an occasional miniature model show what happened when the Teton Dam collapsed in 1976. An estimated 80 billion gallons of water scoured Rexburg, killing nine people….In 2016, after receiving complaints that the Teton Flood Museum didn’t have enough Teton Flood exhibits, the Rexburg city council simply changed the museum’s name to the Museum of Rexburg. But the flood exhibits are still in it.”

[11] Paulson, R.W., Chase, E.B., Roberts, R.S., and Moody, D.W., compilers, 1991, National water summary, 1988-89-Hydrologic events and floods and droughts: U.S. Geological Survey Water-Supply Paper 2375, 591 p.

[12] Find A Grave has an entry for Walter Joe Dealy, noting his death on June 14, 1976, and burial in the Dry Creek Cemetery, Boise, Idaho.