The Idaho Transportation Department closed a 12-mile stretch of state Highway 21, from Banner Summit to Grandjean Road, due to a landslide on Tuesday afternoon.
ITD stated on Facebook around 5:30 p.m. Tuesday that the section of highway will be “potentially” closed for the next two days.
“Drivers should plan alternative routes,” the department said.
The closure came shortly before the National Weather Service issued a flash flood warning for the Highway 21 corridor south of Banner Summit.
“The estimated rainfall rate is 1 to 2 inches in 1 hour,” the Weather Service stated around 7:30 p.m.
The agency also issued a flood watch for the Wood River Valley, Sawtooth Valley and most of southern and eastern Idaho earlier Tuesday afternoon. The watch expires Wednesday evening.
“A surge of deep monsoonal moisture will bring a prolonged period of rainfall … which will result in widespread rainfall totals around 1 inch with locally higher amounts closer to 2 inches possible,” the Weather Service stated.
Forecasters warned of flash flooding in low-lying, flood-prone areas and “especially over recent burn scars.”
For updates, visit 511.Idaho.gov and weather.gov/pih.