2/8/2010
Lack of snow plus avalanche mitigation efforts help keep Idaho 21 safely open for drivers
BOISE - By this time last year, notorious "Avalanche Alley" on Idaho 21 between the Grandjean Junction turnoff and Banner Summit had to be closed to traffic eight days for avalanche mitigation and snow removal.
This year, the total road closures for December and January along the 11.5-mile stretch is three days. By comparison, during that time period last year, the canyon had received 143 inches of snow while this year the total is 99 inches of snow.
For the winter season last year, which runs from December 1 through May 1 in that area of Idaho 21, the canyon experienced 330 inches of snow. Avalanche crews closed the corridor a total of 21 days -- a record low. Prior to that, the average number of closures each year had been 60 days.
"Being vigilant and not over-reacting are the keys," said Bill Nicholson, ITD's Avalanche Forecast Manager.
"We also count on other ITD area crews - particularly from ITD Headquarters, other district offices and the plow crews - and the National Weather Service to do our jobs effectively."
Two years ago, the Idaho Transportation Department (ITD) expanded its avalanche-control measures by adding an experienced avalanche team trained in forecasting avalanches. ITD also added high-tech weather stations and other forecasting equipment, and purchased an avalauncher to fire explosives into weak snowpacks, thereby bringing avalanches down in a controlled manner. To see the avalauncher in action, click here.
The corridor, also known as Canyon Creek, has 54 known avalanche chutes and is responsible for about 90 percent of the state's avalanches.