Recent storms improved Colorado’s meager snowpack. But they also created extreme avalanche risk
This story was originally published in The Colorado Sun.
A storm packing up to 3 feet of snow is headed for parts of Colorado this weekend, building on massive amounts of recent snowfall that raised alarms over avalanche risk in the high country even as it helped ease drought concerns.
It’s great news for Colorado’s snowpack. But for those wanting to explore the mountains to ring in the new year, experts say: beware.
Dangerous avalanche conditions will rise in the coming days as more snow makes it much easier to trigger a slide from low-angle slopes connected to steeper terrain, said Ethan Greene, director of the Colorado Avalanche Information Center. Avalanches are breaking wider and running farther.
“We recorded over 200 avalanches in a three-day period, eight people were buried in avalanches, and one backcountry skier was killed,” Greene said in a statement. “Avalanches are getting bigger; you can trigger them from adjacent flat slopes. They are breaking much wider than people expect.”
Avalanche danger in many parts of Colorado is now high and could reach its highest level, extreme, on Friday, according to the CAIC. Avalanche warnings, indicating that an avalanche is imminent, were issued for Gunnison, Grand Mesa and Aspen areas. Avalanche watches, where avalanche danger is high, were issued for the South and North San Juans, the Front Range and Sawatch zones, Vail and Summit counties, and Steamboat and the Flat Tops.
Danger on the snow-covered slopes could remain long after a storm rolls through.
In the days and weeks after a storm, persistent slab avalanches will pose a significant risk for backcountry adventurers. These avalanches occur when a slab — or a cohesive layer of snow — in the middle to upper snowpack is released as the bond to a lower, weaker layer of snow breaks.
People should avoid traveling in backcountry avalanche terrain, including run-outs in avalanche paths, and being on or under steep snow-covered slopes, experts warn.
Avalanche risk in the backcountry is already high and will increase with the additional snow forecasted for the weekend.
The weather service issued a warning Thursday for most parts of western Colorado ahead of a storm that could bring between 12 to 25 inches of snow and strong winds, with gusts up to 50 mph, Thursday through Saturday morning. Some areas could get up to 3 feet.
Driving could be nearly impossible as patchy snow could reduce visibility, especially in higher elevations and wind chill — as low as 20 degrees below zero — could cause frostbite on exposed skin in 30 minutes, the agency warned.
A prolonged winter storm will continue to impact E UT/W CO through New Years Day. Heavy snow is expected in the mountains resulting in hazardous travel. Check the latest forecast and road conditions before heading out! #cowx #utwx pic.twitter.com/iT4vRwquf4— NWS Grand Junction (@NWSGJT) December 30, 2021
A winter storm watch was also issued for the Front Range and Eastern Plains warning of conditions that could make travel hazardous New Year’s Eve night through New Year’s Day. In Denver, a cold front could bring bitter cold temperatures and 3 to 6 inches of snow, starting Friday through Saturday.
Snow returns Thu into Sat. Moderate to heavy snow could once again create very difficult to impossible travel across the central & SW Mts. Snow expected over the remaining higher terrain by Fri with snow still possible across the plains late Fri into New Year's Day. #cowx pic.twitter.com/5cqODVF1Vl— NWS Pueblo (@NWSPueblo) December 30, 2021
At the start of the month, snowpack in Colorado’s southwestern mountains was dire — the San Juan basin in southwestern Colorado was at a 35% average snowpack. But storms last week helped boost levels to significantly above average for December in many parts of the state, according to the Colorado Climate Center.
The Gunnison River Basin, which had 50% of its normal snowpack earlier this month, is now at 132%, data show.
In 3 weeks, the mountain snowpack went from terrible almost everywhere, to many stations being way above average for late December. The western slopes benefited the most from recent storms, while some stations east of the divide remain well below normal. #cowx #cowx pic.twitter.com/GFQVek24IT— ColoClimateCenter (@ColoradoClimate) December 28, 2021
To stay safe in the backcountry, the CAIC offers the following tips:
- Look at current avalanche conditions online or on your phone using the Friends of CAIC mobile app.
- Every member of a group should carry an avalanche-rescue transceiver, a probe pole, a shovel, and know how to use the equipment.
- Stay on slopes less than 30 degrees steep that are not connected to steeper terrain.