The St. Francis Dam failure occurred in 1928.
Notes on verification
Confirmed by multiple independent authoritative sources including Britannica, USGS, and ASDSO dam failures database, all consistent on the March 1928 date.
Sources
- The Worst: Stupid Engineering Mistakes (wired.com)
- https://www.usgs.gov/media/images/st-francis-dam-disaster (usgs.gov)
- https://damfailures.org/case-study/st-francis-dam-california-1928 (damfailures.org)