To trigger avalanches in Colorado, the state’s Department of Transportation dropped or shot more than 1,500 bombs in mountainous areas that pose avalanche dangers, according to The Durango Herald.
Those explosives, known as avalanche ordnances, are meant to go off during the avalanche mitigation season and lessen the potential for dangerous snow slides, according to KDVR.
While 1,500 explosives were dropped into avalanche paths this season in Colorado, 22 of them were duds and didn’t go off, the Herald reports.
“As a result, the potentially explosive bombs still sit somewhere in the mountains,” the newspaper reported.
Now, the state department is warning hikers to stay away if they come across one, KDVR reported.
“The charges look like large bullets or small torpedoes, according to CDOT,” reports KUSA. “They can be yellow, orange, or blue.”
The transportation department does plan to retrieve the devices that haven’t exploded, KUSA reports, but not until the snow melts.
“It’s not unknown for someone to come across a device that has not detonated, but they are in very rugged terrain,” CDOT spokeswoman Lisa Schwantes said, according to the Herald. “We don’t want to scare anyone, but at the same time, we want to advise the public of the best safety instructions.”
If you see one, you should keep your distance from it and call law enforcement, KDVR reported. The bombs may be covered by snow.
“It’s an explosive, so you definitely don’t want to do anything to move it,” Tracy Trulove with CDOT says, according to the TV station. “A lot of times, it is just a dud and nothing will occur, but you want a team of trained professionals to detonate or disarm the explosive.”
The department is not releasing the exact locations of the 22 potential explosives for “public safety,” KUSA reported, but half of them are near Red Mountain Pass.
“This year was an epic year for avalanches across the state, in particular for Red Mountain Pass,” Schwantes said, according to KUSA. “This pass was closed for close to 19 days this past winter. We had conducted several avalanche mitigation missions within that 19-day period. A couple of the last missions that we did we probably tried to knock down avalanche paths with 20-30 explosives on each of those missions.”
The crews do know where each of the 22 explosives were shot, Schwantes said, and that number is “in line with the national average of about 1 percent chance of a bomb not exploding,” the Herald reported.
The number of unexploded devices may grow as CDOT is planning more avalanche mitigation work, KDVR reported.
“When there is a high risk of avalanche danger, CDOT will close highways at the location of the avalanche path in order to conduct avalanche control,” CDOT says on its website. A video from the department shows helicopters dropping bombs onto the snow-packed mountains before an explosion of snow fills the area, leading to controlled avalanches.
CDOT’s Avalanche Atlas lists more than 522 known avalanche paths, according to its website, and the state controls more than 278 of them.
“During the 2013-2014 winter, CDOT experienced 616 hours of road closures due to avalanche control, resulting in a total of 29,866 feet of snow covering the centerline of the roadway,” the department says. “Crews triggered 283 avalanches with explosives, handled 158 natural occurrences and spent 8,908 hours on mitigation.”