Contractors working for the Colorado Department of Transportation began work Monday to install five avalanche control units along known side paths on U.S. Highway 550 north of the summit of Red Mountain Pass, between Silverton and Ouray.
Traffic delays of up to 20 minutes could occur weekdays beginning July 11, lasting through July 17.
Five avalanche control devices will be constructed along three known slide paths, Blue Point, Blue Willow and Mother Cline.
Blue Willow and Blue Point, at mile post 81, will be controlled using two Gazeks. The devices are remotely controlled and use a mixture of propane and oxygen that, when triggered with a spark, create a sonic concussion with a 328-foot effective radius.
The exploder nozzles are permanent fixtures, mounted on a concrete pad, and fed by gas lines that pressurize the chamber from a remote location.
The Mother Cline slide path, at mile post 89, will be controlled with three O'Bellx systems. Similar to the Gazeks, the O’Bellx can be remotely triggered and uses a mixture of hydrogen and propane gas to create an explosion that will trigger an avalanche.
Unlike the Gazek, the egg-shaped O’Bellx device must be removed from its concrete pad by a helicopter before each season and have its gas supply refilled.
The Mother Cline path will be equipped with the O’Bellx system because the beginning of the slide path is smaller in radius and requires a less forceful blast, and the Gazek is more powerful.
“First and foremost, what CDOT believes is the most significant advantage is safety,” said CDOT spokeswoman Lisa Schwantes.
In the past, crews working to intentionally trigger avalanches (to prevent uncontrolled releases that could injure or kill drivers) had to set charges by hand, use U.S. Military howitzers – World War II-era artillery – or use a “super duper potato shooter” known as an Avalauncher to knock snow loose.
“It’s very hazardous work,” Schwantes said.
The new systems mean that crews will no longer have to directly handle explosives and can work at night, because they will not need daylight visual of the slide path. The slide paths chosen are known as “frequent offenders” and often demand the most mitigation work when heavy snow arrives.
“They (the crews) are really looking forward to that savings in time and manpower,” Schwantes said.
The estimated cost of the project is just under $750,000.
Schwantes said the savings in time will allow crews to focus on other slide paths during storm cycles. She is hesitant to predict whether the installations will lead to passes reopening sooner after storms, given the other slide paths along the highway that must also be mitigated.
Traffic holds of up to 20 minutes can be expected through July 17 as construction ramps up. The project is expected to be completed in October.
rschafir@durangoherald.com
