UDOT PLANNED AVALANCHE CLOSURES!!

Forecast for the Moab Area Mountains

Eric Trenbeath
Issued by Eric Trenbeath on
Sunday morning, March 21, 2021
It is still possible to trigger a deep and dangerous avalanche on a buried persistent weak layer on slopes steeper than about 35 degrees, near and above treeline that face NW-N-E-SE and a MODERATE avalanche danger exists in these areas. Thinner snowpack areas and slopes made up of steep, rocky terrain are the most likely trigger points. Some isolated, unstable wind drifts may also exist in these same areas. Suspect slopes that have a smooth rounded appearance or that sound or feel hollow underneath. Most other terrain has generally LOW danger.
Low
Moderate
Considerable
High
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The Geyser Pass Road has been plowed and is down to the dirt in most areas. Patches of ice and snow exist and it turns muddy as the day heats up. All-wheel-drive recommended.
The Lower Utah Nordic Alliance (LUNA) groomed into Gold Basin on Friday.
Weather and Snow
24 Hour Snow 2" 72 Hour Snow 2" Base Depth in Gold Basin 68" Wind WSW 5-15 Temp 18F
The mountains picked up a couple of inches of snow overnight. Southerly winds cranked in the 20-40 mph range yesterday before backing off around midnight. The passing Pacific trough will continue to deliver unsettled weather to the region for the next 24 hours. Today look for a few light showers and occasional partly sunny skies. Westerly winds will be mostly light with high temps in the upper 20's. Monday looks to be mostly sunny followed by a cut-off low moving into the region on Tuesday and then another system on Friday. None of these systems currently look to be big producers but every little bit helps.
Wind, temperature, humidity on Pre Laurel Peak (11,700')
SNOTEL site near Geyser Pass Trailhead (9600')
Storm totals at the Gold Basin study plot (10,000')
Snowpack Discussion
A few inches of new snow won't do much to soften the range of crusted surfaces underneath, but on sheltered northerly aspects where the underlying snow was still dry, it may provide for a nice refresh. Time and warm temperatures have helped the snowpack adjust to the large snow load we received last weekend but it's still possible to trigger a deep and dangerous avalanche on a buried persistent weak layer of sugary, faceted snow. This weak layer exists on slopes that face NW-N-E-SE, and thin snowpack areas consisting of steep, rocky terrain are the most likely trigger points.
Recent Avalanches
In our travels up to Geyser Pass on Friday, Brian Murdock and I observed this avalanche from the March 13 cycle on a north aspect at around 11,000'. A nasty pocket like this could ruin your day or your life. Note the complex and featured terrain punctuated with rocks. The "pockety" nature of these avalanches leaves you uncertain as to where they may be found, but thin snowpack areas around steep and rocky terrain are the most likely. Steep convexities are also areas of concern.
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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
Most of the avalanches from the last cycle did step down to a layer of weak, faceted snow near the ground, and human triggered avalanches such as this remain possible on similar slopes that have not avalanched. The greatest concern is on wind loaded slopes that face NW-NE-SE near and above treeline. Thinner snowpack areas along slope margins or near rock outcroppings are likely trigger points. Wind loaded slopes should be avoided as should areas of rocky, more radical terrain. Bottom line is that we need a little more time for things to adjust before we strike out into larger terrain. Reduce your exposure by keeping your slope angles below 35 degrees.
The following video of a propagation saw test on a NE aspect at 11,200' illustrates the kind of avalanche problem we are dealing with.
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
With a mostly crusted over snow surface on southerly aspects, there shouldn't have been much snow available for transport during yesterday's strong southerly winds. Nevertheless, there may have been a bit of snow blowing around in the high country so be alert to the possibility of finding shallow, fresh wind slabs on northerly aspects. There may also be a few isolated, old, hard wind slabs hanging around. Suspect smooth rounded areas that sound or feel hollow underneath. You may find them on the leeward sides of ridge crests and terrain features such as gully walls and sub-ridges.
Additional Information
It's amazing what last weekend's storm did for our snowpack which has skyrocketed to 92% of normal. Better late than never.
General Announcements
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.