Poor early season snow causes increased avalanche risk across Colorado
Editor’s note: This story has been updated to clarify what Gilchrist said. He said slides can happen at any depth of snow and in years with such a faceted base like this year, the snowpack will be touchy for a while.
STEAMBOAT SPRINGS — There is “considerable” avalanche danger across the state of Colorado, and three skiers died after being caught up in avalanches over the weekend, one near Crested Butte and two more near Silverton.
While those fatal avalanches took place in the southern half of the state, all but one zone is forecasted to have “considerable” risk for avalanche, meaning that natural avalanches are possible and slides caused by humans are likely.
Ethan Greene, director of the Colorado Avalanche Information Center, said there were more human-triggered avalanches recorded last week than in any week since 2011. Greene said a lot of the almost 900 avalanches they have seen this year have been smaller than some of the landscape-changing ones of 2019.
“The problem with the Colorado snowpack is that we tend to see avalanche cycles that are produced by weather events that create weaknesses in the snowpack that lasts for weeks and months,” Greene said. “That is where we are right now. The dry weather we had in the fall has created a very weak snowpack, so it is not taking a whole lot of snow to cause a spike in avalanche danger.”
A shallow early season snowpack partnered with an extended dry period, like much of the state had in November, is what leads to the weak snow. Greene said this snow, sometimes called sugar snow, changes in structure over time and becomes very weak.
“It is that snowfall in October and then the extended period of dry weather in November,” Greene said. “That is what led to this.”
Dan Gilchrist, a team leader with Routt County Search and Rescue, said when it is really cold at night, there is a lot of vapor transfer in early season snow that is less than 3 or 4 feet deep.
“So you get this vapor moving through the snowpack, and it makes the snowflakes form into these facets or angular crystals that don’t bond together, and that is how you get that sugar snow,” Gilchrist said. “It is super common to have touchy snowpack in the continental U.S.”
When new snow collects on this sugar snow, eventually the weight will reach a tipping point that can cause an avalanche. Gilchrist said that avalanches can happen at any snow depth and in years like this with such a faceted base, the snowpack will be touch for a while.
The last time there was a snowpack like this was nearly a decade ago in the 2011-12 winter season, Greene said, meaning backcountry travelers should not rely on how the snowpack has been in recent years to gauge the safety of a particular area.
“Is it something that you are used to doing? You do this route day after day, year after year,” Greene said. “That route may not be appropriate this year. So you need to give yourself a little wider margin for error.”
The season is really dictated by how the various storms and other weather events come in and the frequency of those events, making it possible for avalanche conditions to improve. But Greene said the snowpack would likely still have similar hazards until melt water is added into the mix in the spring.
Greene said if spring comes gradually, with some melting and freezing of the snow over time, it could make things better for avalanche conditions. But a rapid warming in the spring could make it more dangerous.
Gilchrist stressed it is important to check the avalanche forecast before heading out into the backcountry and let it guide the trip. The Colorado Avalanche Information Center website at avalanche.state.co.us is a great place to check conditions.
“You look at what your planned itinerary is, what you’re doing and then you want to pull the forecast into that aspect,” Gilchrist said. “If you are trying to go above tree line, you look at that part of it. … It helps you make good decisions.”
Greene said it’s important to make sure that what someone plans to do in the backcountry makes sense with current avalanche conditions. He also suggests people have some sort of training about avalanches, whether an online course or a field course.
Gilchrist also suggested backcountry travelers read the case studies when people are caught up and die in an avalanche, so they are aware what has led to an avalanche recently.
“It can make you think about what you need to look out for,” Gilchrist said.
He said it can be tricky to spot avalanche prone areas in Routt County because they are not always obvious, generally being smaller. Still, Gilchrist stressed an avalanche can happen even if there does not seem to be a lot of snow.
“If there is enough snow on the ground to ski or ride, there is enough to slide, there is enough to bury you,” Gilchrist said. “And early season shallow snowpack is always a red flag.”
To reach Dylan Anderson, call 970-871-4247 or email danderson@SteamboatPilot.com.
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