As the water rose in the Boise River in April 1943, officials closed off all but three of the bridges crossing the stream in the Boise area.
Two hundred farm families in the low-lying Strawberry Glen area west of present-day Glenwood Street were evacuated.
Members of the Idaho Volunteer Reserve, formed after the outbreak of World War II, helped evacuate residents and guarded the empty homes.
Unseasonably warm spring weather hastened the snowmelt, increasing the amount of water in the river. At the peak, 25,000 cubic feet per second pushed through the river and across its banks.
The bridges, guarded by airbase troops from Gowen Field, remained closed for five days.
Losses totaled $997,350, with 65 percent of that in the agricultural industry.
With the war, row crops had been planted in Strawberry Glenn and other lowlands. High prices convinced farmers to switch crops.
Topsoil that had remained after previous floods because of the presence of grasses, bushes and trees washed away.
The damage led officials to build the Lucky Peak Dam 10 miles upstream from Boise. The dam was completed in 1955, and flooding has never been as extreme since.