Rain in fire damaged areas trigger landslides

Tailwaters Campground was heavily damaged by the flash flooding.

Last week's rain on top of a lack of ground cover following this summer's fires in the mountains in Elmore County triggered a series of flash floods and mudslides that damaged or blocked roads throughout the area.

A mudslide last Thursday temporarily blocked Highway 20 at milepost 114.5, about 18 miles east of Mountain Home, between the Cow Creek/Prairie Road and the Anderson Dam Road. It took about two hours for the slide to be cleared.

But that wasn't the only incident, just one of the more visible ones.

The short but intense rain event Thursday created numerous flash floods in the area of the Elk Fire Complex along the South Fork Boise River area from Granite Creek, extending east of the Anderson Ranch Dam to Fall Creek.

Ten major drainages had significant mud and debris flows that went over the road system and into the South Fork Boise River and Anderson Ranch Reservoir.

In addition, at least a half dozen creeks that do not have names had mud flows going across the roads, Forest Service officials said.

An Anderson Ranch Dam rain gauge showed nearly half an inch of rain occurred between 6:30-7:15 p.m. Thursday night. Hydrologists with the Burned Area Emergency Response team that had evaluated the burned areas had estimated a half-inch rain event on the severely burned soils would create flash floods.

Elmore County closed several roads accessing the area and the Mountain Home Highway District personnel are working to open the roads. Creeks affected included Pearce, Granite, Rough, Dixie, Mill, Elk, Wilson, Evans, Castle and the Reclamation Village area.

The storm was localized and the Prairie and Pine- Featherville areas did not report any damage.

Due to the storm event, the South Fork Boise River remains closed, which will prohibit rafting from the Cow Creek Bridge downstream to the confluence with Arrowrock Reservoir. The closure is due to the current heavy volume of sediment, logs and other debris in the river.

"We are very concerned of a boater starting a trip downriver in this isolated and limited communication section of the river," said Cecilia Seesholtz, Boise National Forest Supervisor.

"This local area has been hit hard and a lot of work will need to be done to clear the roads and lessen the risks in the river over the upcoming days."

"With the volume of mud coming down the creeks from (Thursday) night's event, and the potential for more flash floods, the public really needs to be aware of hazards," Seesholtz added.

"People should not park in drainages, near trees and be very aware of weather forecasts that call for rain or high winds."

For additional details, contact the Mountain Home Ranger District at 587-7961