Moab Avalanche Advisory

Forecaster: Dave Medara

BOTTOM LINE

Danger by aspect and elevation on slopes approaching 35° or steeper.
(click HERE for tomorrow's danger rating)


Danger Rose Tutorial

Click here to see the newly revised North American Avalanche Danger Scale.

It's a mixed bag out there in the Mountains of SE Utah right now. Good conditions can still be found on shady side slopes below treeline. Sun and wind crusts will be found on above treeline slopes and on sunny sides. In the La Sals, another 3-4 inches of new snow will enhance the goodness, or the challenge depending on where you go. CONSIDERABLE avalanche danger will be found on E-NE-NW-W facing slopes above 10,000 ft where new snow deposits may form pockety wind slabs on open slopes and below ridgelines. We also have some weak older snow out there that is showing severe instability in snowpit tests on these E-NE-NW-W aspects as well. MODERATEavalanche dangers will be found on sunny slopes but skiing and riding conditions will not be very good until we get some established high pressure and some good melt-freeze cycles going on these solar aspects.

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CURRENT CONDITIONS

The storm that lashed Moab last night have moved eastward leaving the La Sals with 3-4 inches of new snow and a big Goose Egg (no snow) in the Abajos. Winds have come around to a more northerly direction this morning with the passage of the storm and a few showers linger over the mountains. Good skiing and riding will be found on shady slide slopes below treeline where sun and wind haven't crusted over the old snow surface. We have about 74" of snow on the ground at our Gold Basin Study plot in the La Sals and we're at 129 - 138% of normal across the region.

Expect 4wd or Chains to be necessary to get to the La Sal trailheads this morning until Plow Crews can get up on the Mountain. Access to the Abajos should not be a problem.

Matt Hebbard, our hero, has once again single handedly groomed the entire La Sal Nordic system. In this case only to have it covered by yet another storm. Powder Skating and Classic cross-country await. Good work Matt.


RECENT ACTIVITY

Nothing observed yet but this last storm will mostly cover up the drama of the 2/21/10 avalanche cycle.


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 48 hours.

WInd slabs in the new snow are our primary avalanche danger today. E-NE-NW-W facing slopes steeper than 35 degrees near and above treeline will have wind loaded areas of sensitive new snow from last nights storm. Other areas could be cross loaded by moderate-strong winds from the south last night also. There wasn't a lot of new snow with this quick - hitter last night, we just have to look out for where the winds may have drifted it to dangerous levels.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 48 hours.

Click here to see the newly revised North American Avalanche Danger Scale.

Secondly, we still have major, pretty scary structural problems with our old snow. I was hoping that with our increasing depth, we would start to see a strengthening of the snowpack, but that hasn't taken place just yet. We are seeing a decline in the avalanche danger rating based more on the passage of time with no major new snow, than on a strengthening of the persistent weak layers in our snowpack.

Most notably, is the presence of of a buried layer of Surface Hoar about 34-38" below the snow surface. This layer failed repeatedly in snowpit tests Tuesday showing very clean shears and the ability to propogate over distances, citing the potential for slab avalanche release. Seriously, it was popping out of snowpits like a cash register opening. I was hoping to see stronger results on that layer, but surface hoar in particular can remain active for weeks once buried. This weak layer does not seem to be everywhere, unfortunately, the most likely place to find it is on E-N-NW facing slopes at and below treeline that are relatively open. Exactly where the best skiing is likely to be found. Areas with a thick tree canopy won't have and above treeline slopes are unlike to have it as well. It appears as a gray band about 1/2 thick in a snow profile. Do yourself a favor and take a look for this layer before you dive into anything steeper than about 35 degrees on shady side slopes.


THREAT #3

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

These may not be a problem today with remaining cloud cover, but watch out for wet slides on the sunny aspects when the sun pops out either today or tomorrow. Get off the sunny sides before they get too warm. Rollers balls and point releases from rocks trees or your skis are an indicator that it is time to move to a cooler or less steep slope.


MOUNTAIN WEATHER

National Weather Service Forecast for 10,000 Ft. :

Today:

Snow showers, mainly before 11am. High near 27. West southwest wind around 10 mph. Chance of precipitation is 90%. Total daytime snow accumulation of 1 to 3 inches possible.

Tonight:

Partly cloudy, with a low around 16. West northwest wind around 5 mph becoming south southeast.

Saturday:

Mostly sunny, with a high near 38. Northeast wind 5 to 10 mph becoming south.

Saturday Night:

A 30 percent chance of snow, mainly after 11pm. Cloudy, with a low around 23. Breezy, with a southeast wind 10 to 15 mph increasing to between 20 and 25 mph. Winds could gust as high as 35 mph.

Sunday:

Snow, mainly after 11am. High near 33. South southwest wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 80%.

Sunday Night:

Snow. Low around 17. Chance of precipitation is 80%.

Monday:

A 30 percent chance of snow, mainly before 11am. Mostly cloudy, with a high near 29.

Monday Night:

Mostly cloudy, with a low around 18.

Tuesday:

A slight chance of snow. Mostly cloudy, with a high near 33.


GENERAL ANNOUNCEMENTS

We would like to thank the hard working volunteers at the Friends of the La Sal Avalanche Center. Without their help the center would not meet it's funding or staffing requirements. Thanks all! If you would like more information about donating to the Friends or simply helping out, click here..

This advisory will expire in 48 hours.

We cannot receive messages on our 259-SNOW line. If you would like to leave us an observation or a message, you my reach us at 435-636-3363.


This information does not apply to developed ski areas or highways where avalanche control is normally done.  This advisory is from the U.S.D.A. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.


This advisory provided by the USDA Forest Service, in partnership with:

The Friends of the Utah Avalanche Center, Utah Division of State Parks and Recreation, Utah Division of Emergency Management, Salt Lake County, Salt Lake Unified Fire Authority and the friends of the La Sal Avalanche Center. See our Sponsors Page for a complete list.