The scoop on spring snowpack |

The scoop on spring snowpack

SUMMIT COUNTY – Many people wait until spring to embark on backcountry adventures, but while avalanche dangers might not be as high as they are in February and March, they are far from non-existent. In Colorado, there have been more than 2,000 avalanches so far this season, six lives have been claimed, and avalanche researchers emphasize that the season’s not over yet.

“Spring can bring even more complicated snowpack than the middle of winter,” said Scott Toepfer of the Colorado Avalanche Information Center (CAIC).

“April is probably the third or fourth most active month for avalanche fatalities. February tends to lead, and March and January are neck and neck. In April, a lot of people say, `Hey, it’s spring. Isn’t that what they said in the avalanche class, that the safest time to ski is spring?'”

It’s hard to deny spring has arrived when ski area visitors are wearing T-shirts and shorts, but as Toepfer points out, on higher elevation backcountry terrain, especially on certain aspects, snowpack and ski conditions are not always spring-like.

“You have to really ask, is it really spring in some of these avalanche paths?” he said.

“We’re down in Frisco, walking to a coffee shop in a T-shirt, but you go up to 12,000 feet, and it’s still cold. On colder, northerly aspects – north to northeast – the snowpack is still pretty cool. This is something that has gotten people into trouble in the past. On a south-facing slope, all through the winter, it gets snow, it gets baked. It gets more snow, it gets baked. Avalanches are running on those shallow layers. We’re coming into quite a thaw cycle here.”

The thaw cycle is what separates the physiology of wet, spring slides from mid-winter slides. If conditions are spring-like, it does not mean they are stable, especially in mid to late afternoon on warm days. Avalanche educators point out that spring snowpack brings a brand new line up of dangers.

“In the winter, vapor goes to the surface of a snowpack,” said Brad Sawtell, forecaster for the Summit County Office of the CAIC. “In the spring time, that effect is reversed. The moisture goes below and turns to free running water. Water percolates down through the snowpack, and water is always going to take the path of least resistance. So, once that water reaches a dense layer, rather than go through it, it’s going to run off.”

Avalanche center representatives advise backcountry travelers to follow the same safety protocols in the spring as they do in the winter – dig a couple pits to get a good idea what the layers look like in the snowpack, have escape routes planned and make ski cuts at the top of a slope before skiing down it. In spring, there are a couple other ways to determine the stability of the snowpack.

“People, in the back of their minds, they think, I won’t go backcountry skiing or riding until spring time, because that’s when things are stable,'” Sawtell said. “Sometimes they are and sometimes they’re not. Two good rules of thumb when you’re out in the spring are, if your ski boots penetrate the snow to the top of your boot, it’s probably time to go home. And, when I’m out there, I continuously scoop up handfuls of snow. If there’s too much viscosity – if you can squeeze water out of it – it’s time to leave. If there’s several bluebird days in a row and if you’re out in the backcountry at 3 or 4 in the afternoon, you should wonder why you’re there.” On warm days, backcountry skiing is safest in the morning when the snowpack is still firm.

Sawtell said wet slides can occur on lower-angle slopes than slides in mid winter, because once the snow warms up and turns slushy, the water in it is going to run downhill regardless of how steep the slope is. He also said the above-average snowfall this winter hasn’t made for more or less stable snowpack per say, it just means “there’s more snow capable of causing an avalanche.”

Toepfer believes the freeze-thaw-freeze cycle this winter has built a fairly stable bridge for backcountry travelers, but he still emphasizes the potential danger and possibility of wet slides.

“People die in avalanches in April,” he said. “In Colorado, people have died in avalanches every month but September. In the spring, as soon as it starts getting wet, you’ve got issues. If you find yourself in a Slurpee, it’s time to go back to the barn.”

Safety tidbits for spring backcountry travel from the Colorado Avalanche Information Center:

Snowpack is safest in the morning when it is still firm.

If you can squeeze water from a handful of snow, the snowpack is unstable.

If you sink past your ankles in the snow, it’s not stable.

Dig a snow pit to determine what kind of sheer layers exist in the snowpack.

Don’t travel alone, bring all safety equipment – beacon, probe and shovel – and know how to use it.

Have an escape route planned and make ski cuts at the top of a slope before skiing down it.

Check current snow conditions by calling the CAIC hotline at (970) 668-0600.

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