On a scale of one to five, the current avalanche danger in the La Sals is listed as Level 2, or moderate, according to local Utah Avalanche Center forecaster Eric Trenbeath.
At this time of year, avalanches typically occur on shady north-facing slopes that are steeper than 35 degrees, and the latest forecast at http://utahavalanchecenter.org cautions that persistent slabs in these areas are still a concern.
As of mid-week, the odds that someone could trigger these buried slabs had grown less likely. Just to be on the safe side, though, Trenbeath advises skiers, snowmobilers and other backcountry visitors to steer clear of these areas altogether.
“This type of terrain can lure you far down a slope to where if a slide is released, it will fracture well above you,” he said.
That’s not the only potential danger they face. There are two other types of avalanches that backcountry visitors should be aware of this week, as well.
Strong winds from the north and northwest have blown snow around the higher reaches of the La Sals, forming pillow-like wind slabs along ridge crests.
The slabs, which take shape when wind-blown snow settles on top of weak layers, are especially common on eastern and southerly aspects at higher elevations. But Trenbeath cautions that similar conditions may also exist on the leeward side of terrain features.
Wind slab-related danger was expected to drop between Dec. 18 and Dec. 19. At the same time, though, warmer weather is creating a third avalanche danger on south-facing slopes that are steeper than 30 degrees or so.
As daytime mountain temperatures rise to the mid- to high-30s, wet slide activity in those sunny areas becomes a concern. Visitors should keep an eye out for signs of instability, including wet and slushy snow, and as the weather warms up, they should avoid steep south-facing areas altogether.
Right now, the best conditions in the La Sals can be found in sheltered northerly aspects below the tree line.
Snow depths vary across the range, with about three feet of snow at Gold Basin and 21 inches at the Geyser Pass trailhead.
“We’re off to a pretty good start as far as the snow depth goes,” Trenbeath said Dec. 16.
As the season continues, Trenbeath will be providing regular updates on the Utah Avalanche Center’s Moab-area advisory page at http://utahavalanchecenter.org/advisory/moab. The site features an interactive map with color-coded avalanche advisories for the La Sal and Abajo ranges, as well as other mountains across the state.
At some point in the near future, Trenbeath will also be hosting an avalanche awareness class.
For now, he leaves backcountry visitors with a simple reminder that avalanches don’t happen by pure chance. More than ninety percent of avalanche victims trigger the events that they get caught up in.
Anyone who visits the backcountry this time of year can cause an avalanche. But as a group, snowmobilers are most at risk.
“The machines have gotten so much more powerful that they can high-mark onto high-avalanche slopes that they were formerly incapable of reaching,” he said.
Education is key to reducing that risk, and it’s a major component of his new job as the avalanche center’s forecaster at the Manti-La Sal National Forest’s district office in Moab.
Although relative newcomers to town might know him as the owner of the Framed Image, Trenbeath previously held the same forecasting post from 1999 to 2003. Before then, he spent many a winter at Alta Ski Area, which is well known for its extensive avalanche control program.
Given those experiences, Trenbeath is happy to be back out in the field after a 10-year break.
“I missed being outside, and I missed being in the snow,” he said.
He plans to spend some time indoors at the Framed Image, though. The business will be open primarily by appointment only from Christmas Day through early February; customers who would like to schedule an appointment can call 259-4446.
For more information about avalanche conditions, call 435-259-7669.