3/7/2014
U.S. 12 closures reflect regional avalanche activity
BOISE – Recent closures of a section of U.S. 12 are part of a larger regional pattern that has seen an increase in the risk of avalanches, the Idaho Transportation Department announced.
“Avalanche danger throughout the American West has been unusually high for the last month, and avalanche terrain affecting U.S. 12 along the Lochsa is no different,” said Bill Nicholson, an avalanche forecaster with the Idaho Transportation Department.
Nicholson said existing snowpack on the ground has created an unstable foundation, which can be undermined by significant amounts of rain and unusually high temperatures that are forecasted.
Since Feb. 12 of this year, U.S. 12 between milepost 100 and milepost 161 has closed five times because of avalanche danger. When a closure occurs, gates across the highway prevent access as a safety measure.
The most recent closure started on Thursday (March 6) afternoon. The highway remains closed, and there is not an estimated re-opening at this time. Intermittent closures are expected until weather conditions change.
It is a significant number of closures compared to previous years. Before Feb. 12, U.S. 12 closed twice since 2008 because of potential avalanches.
A section of Interstate 90, which is north of U.S. 12, closed March 4 between Mullan, Idaho, and St. Regis, Mont., because of potential avalanches. This was the first closure of the highway because of avalanche danger since January 2008. A section of I-90 in the Snoqualmie Pass area in Washington has seen many closures this year because of avalanches.
In southern Idaho, Idaho 21 has experienced at least 75 slides so far this year. More than 30 of those have reached the highway. The largest has been 50 feet deep.
There have been no fatalities on Idaho highways caused by avalanches. But from late December 2013 through March 5 of this year, there have been 20 fatalities in Western states. These were recreationists who were snowmobiling, hiking, skiing and climbing.
During winter months, drivers are encouraged to call the Idaho Traveler Services at 5-1-1 for the latest highway and weather conditions. For online updates, visit the website at 511.idaho.gov. Telephone and Web reports are available 24 hours a day and are updated as conditions change.