Wednesday, October 18, 2017

How to start an avalanche: CDOT preps Gazex exploders for coming winter months

#Colorado
Courtesy Gazex

Summit Daily News Link


Avalanche mitigation workers with the Colorado Department of Transportation are gearing up for the coming winter onslaught.
Workers from CDOT and the Colorado Avalanche Information Center (CAIC) over the last few weeks have been working to prepare avalanche control equipment located on Berthoud Pass and Loveland Pass for the coming winter.
The state has several different options for mitigating — basically intentionally setting off — avalanches in the Rockies, including artillery pieces and pneumatic cannons called avalaunchers. But at two locations in Colorado, Berthoud Pass and Loveland Pass, the state also utilizes a system called Gazex.
Made by the French corporation, TAS, Gazex is an avalanche control system that uses specially constructed “exploder” sites and tubes built at key locations in avalanche territory to set off avalanches at controlled times. The exploders literally detonate a mixture of oxygen and propane from the tube structures. The explosive force expelled from the tubes triggers avalanches. The explosive bursts are fueled by gas canisters stored in tanks beneath the exploders on the mountain.
Three weeks ago, CDOT crews began working to remove old tanks left from last year’s avalanche control work. To accomplish their goal, a helicopter was used for most of the heavy lifting, ferrying the empty industrial gas canisters down to the Clear Creek Valley, far below the Gazex sites high on the Stanley Slide on Stanley Mountain.
CDOT was back at it last Friday, hauling helicopter loads of gas canisters back up the mountain, before they were loaded into the Gazex stations for mitigation work in coming months.
Highway 40 was intermittently closed Friday near Berthoud Falls to accommodate the work.
The state has five Gazex stations servicing Berthoud Pass and 11 for the Loveland Pass area.
As snow starts piling up later this winter, CDOT and the CAIC closely monitor passes throughout the state. Determining when to use a Gazex system, or other avalanche control devices such as howitzers, is a complicated process that relies heavily on input from the CAIC.
Monitoring avalanche prone areas involves multiple different strategies from on the ground snow surveys, to spotters looking for danger spots, to remote sensory equipment that provides data on how much snow has built up on specific mountain slopes.
Officials from CDOT say the state has plans to expand the Gazex avalanche mitigation system throughout the state to passes where the equipment will be beneficial, though they acknowledged not every pass in the state is conducive for a Gazex system. The state works closely with the CAIC to determine which passes are most suitable for a Gazex system.