The Teton Dam Failure – An Effective Warning and Evacuation

Teton Dam, the highest dam to ever fail in the U.S., failed on Saturday, June 5, 1976 during its initial filling. Nearly 800 homes were destroyed, 3000 homes were damaged, 35,000 people were evacuated and 11 people died. The peak dam failure outflow was more than 2,000,000 cubic feet per second. Flooding eventually covered 185 square miles. No formal emergency action plan or dam failure inundation maps existed for Teton Dam. The presentation will delve into the following topics: (1) The specific dam failure scenario that took place. (2) The ideal time for the failure to occur (at about noon on a warm sunny day. (3) Flood characteristics: depths, rate-of-rise, and flood wave travel times. (4) Destruction in the various impacted communities. (5) The sequence of events that led to the issuance of a warning. (6) Warning time in downstream areas. (7) Methods that were used in disseminating the warning. (8) Why did people evacuate? (9) How many people evacuated? How many did not? (10) Which communities experienced dangerous flooding? (11) The circumstances associated with the people that died. Lessons learned from this event will be presented. 30 pp., 3 tables, 2 figures, 27+ references.