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Forecast for the Moab Area Mountains

Eric Trenbeath
Issued by Eric Trenbeath for
Monday, January 23, 2023
A MODERATE danger exists for human triggered avalanches involving slabs of wind drifted snow on all aspects primarily above treeline. Drifts may also be found at lower elevations in wind exposed terrain so keep your eyes out for smooth, rounded deposits of wind drifted snow.

On northerly aspects, a low probability/high consequence scenario remains for dangerous, human triggered avalanches failing on a buried persistent weak layer. Thinner snowpack areas, and areas of very steep, rocky, radical terrain are where you are most likely to find this problem.
Most other terrain has generally LOW danger.
Low
Moderate
Considerable
High
Extreme
Learn how to read the forecast here
Special Announcements
The USFS is bringing in a bulldozer today to widen the Geyser Pass Road and open up the parking lot. The road will be closed while work is in progress and it may take a few days. Please be patient.
Weather and Snow
24 Hour Snow 5" 72 Hour Snow 5" Season Total Snow 174" Base Depth at Gold Basin 80"
Winds on Pre Laurel Peak E 10-15 Temp 16

Weather
A closed low tracking through AZ brought a quick burst of snow to the La Sals early this morning. A chance for light snow will continue this morning with gradual clearing later today. East winds will continue to blow 10-15 mph, and high temps will creep up into the low 20's. NW flow takes over with a weak shortwave clipping by on Tuesday night followed by dry and mostly clear weather through the remainder of the week.
General Conditions
5" of new snow will provide a nice refresh and conditions remain quite good. Easterly winds have continued to form fresh drifts, primarily above treeline. Be on the lookout for unstable slabs of wind drifted snow on the leeward sides of ridge crests and terrain features such as gully walls and sub-ridges in wind affected terrain. The November persistent weak layer (PWL) was given a significant load test last week. We observed one large avalanche that failed on the weak layer. The odds of triggering this kind of avalanche with the weight of a skier or rider are unlikely, however it still may be possible in outlying areas that have a combination of radical terrain and a thinner, weaker snowpack.
For more snowpack information see a complete list of observations here.

Snowpack and Weather Data
Gold Basin Storm Stake (10,000')
Gold Basin SNOTEL site (10,000')
SNOTEL site near Geyser Pass Winter Trailhead (9600')
Wind Station on Pre-Laurel Peak (11,400')
NWS forecast for the La Sal Mountains.
Recent Avalanches
No new avalanches have been reported since the one we observed last Thursday. For a complete list of avalanches see the La Sal Avalanche database here.
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Avalanche Problem #1
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
5" of new snow combined with wind keeps the threat of human triggered avalanches involving wind drifted snow alive on all aspects above treeline. Be on the lookout for unstable slabs of wind drifted snow on the leeward sides of ridge crests and terrain features such as gully walls and sub-ridges in wind affected terrain. Fresh drifts often have a smooth, rounded appearance and cracking is a sign of instability.
Older drifts that formed over the last few days will be covered up now, and though they have mostly stabilized, steep slopes that have a smooth, rounded, "fat" appearance should be approached with caution, especially slopes that have steep convexities. In very isolated, thinner snowpack areas, an avalanche triggered in the wind drifted snow could to step down to the November PWL causing a deeper and much more dangerous avalanche.
Avalanche Problem #2
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
If you've been following along, you know that The November persistent weak layer (PWL) has been gaining strength and is deeply buried in most areas. Prior to last week's storm event, the last round of avalanches failing on this weak layer was during the New Years storm cycle. Before putting this problem to bed so to speak, we wanted to see what the most recent load of heavy snowfall would do, and lo and behold, it produced a very large avalanche. Avalanche activity was not widespread, and stability tests indicate that the odds of a skier or rider triggering this kind of avalanche are unlikely, however it still may be possible in outlying areas that have a combination of radical terrain and a thinner, weaker snowpack, particularly on slopes facing the north side of the compass.
Photo illustrates what is now a thin weak layer of faceted snow about a meter below the surface. The weak layer used to be much thicker, and then snow beneath was much weaker and looser. Time, and compressive weight from above has helped to strengthen this layer, but it was still capable of producing an avalanche under the stress of a rapid, heavy load.
In most areas, the weak layer is deeply buried, and hence very difficult, if not impossible to affect by the weight of a skier or rider. The trick then, is to avoid areas where the snowpack is thinner such as in wind exposed terrain, along slope margins and near rocky outcrops, and in areas of very steep, rocky, radical terrain.
Additional Information
What's happening to the persistent weak layer? Salt Lake forecasters Nikki Champion and Dave Kelly discuss what has happened to it in the Wasatc Mountains. Down here in the La Sals we are trending toward this scenario.
General Announcements
This forecast is from the U.S.D.A. Forest Service, which is solely responsible for its content. This forecast describes general avalanche conditions and local variations always occur. This forecast will be updated by 7:30 tomorrow morning.