Forecast for the Moab Area Mountains

Eric Trenbeath
Issued by Eric Trenbeath on
Tuesday morning, February 4, 2020
Blowing and drifting of the recent snow has created a CONSIDERABLE avalanche danger, and human triggered avalanches are likely on steep, wind drifted slopes. Most drifting has occurred on slopes facing the north side of the compass, but with the strong and gusty nature of the winds, you may find areas of unstable wind drifted snow on all aspects. On most south-facing terrain you will find a MODERATE avalanche danger. Wind drifts are recognizable by their smooth, rounded, or rippled appearance, and cracking is a sign of instability. In areas where the underlying snowpack is shallow and weak, a triggered wind slab may step down to a buried persistent weak layer causing a deeper and more dangerous avalanche. Avoid steep, wind drifted slopes today.
Low
Moderate
Considerable
High
Extreme
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Special Announcements
Are you looking to improve your avalanche skills? We are offering a Backcountry 101: Introduction to Avalanches class on February 15-16 in Moab. Click here to register A huge thanks to Moab Gear Trader for sponsoring this course. Please visit them for all your winter backcountry needs.
New UAC Podcast: The Art of Storytelling Through Film - A Conversation with Trent Meisenheimer check it out HERE.
Road Conditions: Grand County plans to plow today but they also have the Loop Road to contend with so timing is uncertain. The gate will be closed while plowing is in progress. If you plan to beat the plow, expect up to 6" of snow on the road with deeper drifted areas. I drove it yesterday and it was pretty exciting.
Grooming report: LUNA (Lower Utah Nordic Alliance) is planning to groom on Wednesday.
Weather and Snow
24 Hour Snow 10" Weekly Snow 17" Base Depth in Gold Basin 53" Wind N 10-15 mph Temp -2F
Weather: "Under promise and over-deliver" was how fellow Wasatch forecaster Drew Hardesty put it last week. A solid 10" of new snow fell in Gold Basin by late afternoon yesterday with 8" at Geyser Pass Trailhead at .8 to 1.0" of water weight. I expect well over a foot of new snow fell up high. Strong southerly winds blew most of the day yesterday averaging 40 mph with gusts in the low 60's until they slowly started to back off around noon. By evening they had shifted to the NW becoming calm around midnight. Under sunny skies, it's going to be frigid up there today with light to moderate northerly winds, and a high temperature of 10 degrees. The next system to affect the region will move in Wed-Thu but it looks to be on a more northerly track.
Snowpack: In spite of my pessimism yesterday, snow conditions are greatly improved though you can still feel the underlying base, particularly on south aspects. I did not make it above treeline yesterday, and I still expect to find scoured and alternately drifted surfaces up there, but in sheltered terrain below treeline, the new snow has stacked up nicely and conditions will be great out there today.
Underneath, the snowpack is variable. In most areas above about 10,500', the pack is deep and strong with a depth of 4'-5'. But sun and wind-exposed slopes, and rocky areas right around treeline and below have shallower and weaker snow. Up to an inch of water has been added to these weaker snow areas, and we'll need to pay attention to how well they are able to support the new load.
Wind, temperature, humidity on Pre Laurel Peak (11,700')
Storm totals at Gold Basin Study Plot (10,000').
Snotel site near Geyser Pass Trailhead (9600').
NWS weather forecast
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Avalanche Problem #1
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Turns out there was plenty of new snow available for transport and yesterday I observed lots of blowing and drifting of the new snow, even at lower elevations. At upper elevations, expect to find deep drifts up to 2' deep. Most drifting has occurred on slopes facing the north side of the compass, but with the strong and gusty nature of the winds, you may find areas of unstable wind drifted snow on all aspects. Wind drifts are recognizable by their smooth, rounded, or rippled appearance, and cracking is a sign of instability. In areas where the underlying snowpack is shallow and weak, a triggered wind slab may step down to a buried persistent weak layer causing a deeper and more dangerous avalanche. Avoid steep, wind drifted slopes today.
Avalanche Problem #2
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
We've been seeing some cracks develop in our generally strong snowpack, particularly in our mid-elevation band just below treeline. In these areas, the snowpack is shallower, between 3'-4' deep, and layers of weak faceted snow are beginning to develop. This storm, with an inch of water weight, is the second incremental test of these buried weak layers. Add drifting and the load may be significant enough for a skier or rider to trigger a deeper and more dangerous avalanche. Avoid steep, wind drifted slopes, especially in areas where you suspect the underlying snowpack is shallow and weak.
We've also been tracking a reactive weak layer on SE-S facing slopes. I'm hoping the warm temps over the weekend have helped put an end to this concern but until I get eyes on it myself, I can't be certain.
General Announcements
My radio interview on KZMU about the history of backcountry skiing in the La Sals, avalanche accidents, and unique snowpack has been saved in perpetuity. You can listen to it here.
Check out the avalanche beacon training park at the Geyser Pass Trailhead and practice your rescue skills!
This forecast is from the U.S. Forest Service, which is solely responsible for its content. This forecast describes general avalanche conditions and local variations always occur.