Skiers and snowmobilers have triggered six avalanches in the past week or so across the San Juan Mountains as deteriorating snow conditions have upped the chances of starting a slide.
According to the Colorado Avalanche Information Center, recent fresh snow and strong winds have built shaky layers of snowpack, which sit on top of weaker, more fragile layers from previous storms.
CAIC forecasters on Monday went to more closely inspect snowpack conditions, finding the new slabs that were formed during recent warm temperatures were touchy and prone to slides.
“A sliding surface may give an extra boost, and avalanches failing above this crust could run fast, far and break wider than expected,” CAIC reported. “Trigger a shallow slide below new or wind-drifted snow has potential to break deeper in older, weak snow creating a larger and more dangerous avalanche.”
An uptick in avalanches started by backcountry travelers started Jan. 19 – yet so far, no one has been injured.
The first was a reported slide set off by a skier on the east side of Chattanooga, around 5:30 p.m. A witness reported a skier was traveling a steep bank about 20 feet wide when the snowpack broke.
On Jan. 20, a skier set off a 10- by 20-foot avalanche on a slope between Howardsville and Middleton, north of Silverton.
The next day, an avalanche was reported near Snowslide Gulch and Bay City, up La Plata Canyon, at an elevation of about 10,300 feet. A witness said the avalanche ran about 500 vertical feet, with a maximum crown of about 8 inches, referring to the size of the part that broke away.
On Thursday, two snowmobilers were riding in the upper Bear Creek drainage above the Colorado Trail, near Molas Pass, when an avalanche broke. One rider was able to ride up and over the debris pile, while the other was caught and rode the slide to the bottom.
The witness who reported the incident said they could not determine whether the rider was caught in the slide, which traveled an estimated 300 feet, was about 500 feet wide and had a crown of about 18 inches.
On Friday, a skier triggered an avalanche at an elevation of 13,200 feet, but the report did not have additional information.
And Sunday, a slide was triggered near Alta Lakes by Telluride, traveling about 200 feet with an estimated crown of 14 inches.
On Tuesday, the avalanche danger for the South San Juans and the North San Juans was listed as moderate and considerable, respectively. CAIC forecasters say the North San Juans are a little more dangerous.
“Below treeline there is also ample new snow, more near Telluride and Red Mountain Pass, so watch for storm snow to be sensitive there,” the report said. “Avoid smooth, rounded pillows below ridges and cross-loaded terrain features. Safer riding conditions can be found on lower angle, wind-sheltered slopes.”
In the San Juan Mountains, there have been 35 avalanches triggered by recreationists reported to CAIC this winter. The only death so far this season in the San Juans has been a woman who was killed by a large piece of ice that naturally broke off, causing a cascade of snow and ice to come down, while ice climbing near Ouray on Jan. 18.