Different conditions so far for the Aspen area snowpack
December 17, 2015
The Aspen-area snowpack hasn't set up in the typical way — no early season snow rotting during a lull in storms and deteriorating into a weak, dangerous base, according to Colorado Avalanche Information Center forecaster Blase Reardon.
But Reardon warned backcountry adventurers in a presentation Wednesday night not to let their guard down yet. Conditions can change lickety-split.
Avalanche conditions in the Aspen zone, which includes the Crystal and Fryingpan valleys, have been "low" and "moderate" for most of the season. The rating has increased to "considerable" at times following high winds.
Conditions have been a product of what Mother Nature delivered — or didn't deliver.
“Things have been very good so far; things might get tricky soon.”Blase Reardon, Colorado Avalanche Information Center
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There was no measurable snowfall until late in October — later than most recent seasons. That meant Colorado avoided "the classic situation" with its snowpack, according to Reardon.
"The season did start a little late and that's significant because that means we don't have a lot of depth hoar at the base of the snowpack on most slopes like we often do," Reardon said.
Depth hoar is defined by the National Avalanche Center as large-grained, faceted, cup-shaped crystals near the ground. It forms when there are large temperature gradients within the snowpack. That usually happens when a big storm or storms blow in during October, then temperatures rise and precipitation disappears.
Along with the late start to the season this year, there's been regular though not prodigious snowfall. The snowpack is close to average. There isn't a lot of depth hoar and generally not a lot of weak surface layers of snow.
Normally at this point the Aspen zone would be experiencing a "long string of avalanche activity," Reardon said. "People would be triggering it over and over and over.
"We've really had moderate or low (ratings) most of the season so far," Reardon added. "Would we expect to be at moderate or low with depth hoar snowpack? No."
His presentation was an informal chat with an audience of about 25 people, including many Aspen skiers who either make a living heading into the backcountry or are accomplished recreational skiers. Aspen Expeditions, which offers guided backcountry trips, sponsored the presentation at the Highlands Ale House at the base of Aspen Highlands. Aspen Expeditions owner Dick Jackson said he has planed monthly events this winter where backcountry adventurers can get together and exchange information in an informal setting.
Reardon urged the audience to use the "observations" section of the Colorado Avalanche Information Center website to report what they are witnessing. The site is at http://avalanche.state.co.us. The center is only as good as the people who are getting out into the backcountry and sharing information, he said.
Reardon noted that the storm that swept through Colorado on Monday and Tuesday dumped anywhere from 3 to 30 inches of snow in the Aspen zone. That could bring quick changes.
"Now we have a potential weak layer at the surface, weaker snow in shallow areas with a slab potentially forming on top of it," Reardon said. "Things have been very good so far; things might get tricky soon."
It all depends on what happens with snowfall in the next week or so. He urged backcountry travelers to remain alert and not get overconfident.
"This is not a license to do whatever you want, alright?" Reardon said. "But we don't have that classic setup. Things may get really interesting in the next week, or they may not, depending on how much snow that we get."