Uintas Avalanche Advisory

Forecaster: Grant Helgeson

SPECIAL ANNOUNCEMENT

Come join forecasters from the UAC along with the talented athletes from Boondockers for our second annual Essential Avy and Riding Skills Workshop. Click here for more details.


BOTTOM LINE

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


Danger Rose Tutorial

At mid and upper elevations the avalanche danger is MODERATE (Level 2) on steep wind drifted slopes and human triggered avalanches are possible. Be aware that within this elevation band a CONSIDERABLE (Level 3) avalanche danger also exists, especially in steep, shallow, rocky terrain, facing the northwest through southeast. While not widespread and pockety in nature, dangerous human triggered avalanches are still possible.

A LOW (Level 1) avalanche danger exists in lower elevation terrain, especially on sun exposed slopes and those not effected by wind.


CURRENT CONDITIONS

Yesterday's minor storm left us with a meager 3" - 4" of total snowfall. This morning, things are chilly on the North Slope with Lilly Lake coming in at 12 F. Temperatures average 20 F at 8,000' & 15 F at 10,000'. Upper elevation winds are relatively well behaved; averaging 10 mph out of the south, gusting to around 20 mph. Total snow depths at the upper elevations throughout the range are just about four feet. Despite the lack of snow, riding and turning conditions remain quite good.


RECENT ACTIVITY

In recent news of the weird- Ted spotted a rather large, natural avalanche that was a few days old, occurring on a southeast facing slope on Moffit Peak. The slide was 2’-3’ deep, 250’ wide, failing on weak, sugary snow near the ground. We’re kinda scratching our heads on this one, but after reviewing data from our wind sites, it looks gusty northwest winds on the evening of the 4th are the likely culprit.

Jim and I found evidence of a recent natural cycle on north through east aspects in Soapstone Basin. One avalanche on a north facing slope looked fresh, likely running in the last 72 hours.


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Persistently weak, Continental snowpacks like the western Uinta’s are challenging at best. They’re difficult to predict and even harder to forecast for. Just when you think you’re turning a corner with the strength of the pack you hear about a slide breaking into weak snow near the ground… in February no less! As we’ve seen with our snowpit stability tests, in some areas where the snow is deep, say 4’-5’, the pack is gaining strength and you’d have a hard time triggering a dangerous slide. However, in terrain where snow depths remain shallow, say three feet or so, we can easily affect the weak layers of snow, subjecting them to a rapid change and trigger a scary slide which breaks to the ground. While these conditions are getting harder to find and you can ride miles and miles of terrain without even dealing with this avalanche dragon, be aware- this problem child still lurks in our snowpack. Likely suspects are steep, rocky slopes at mid and upper elevations in terrain facing northwest through southeast.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

There’s been enough upper elevation wind overnight to transport snow, creating manageable fresh drifts which break at or below our skis or sled. You’ll find these wind slabs on leeward terrain facing northwest, north, northeast, and east along with some cross-loaded slopes facing southeast. Today, you’ll want to continue avoiding any fat looking, wind loaded slope. As evidenced by the recent avalanche on Moffit Peak, even shallow slides can break into weaker snow as they descend the slope, creating a larger avalanche than you might expect.


MOUNTAIN WEATHER

Today we'll see overcast skies with temperatures topping out in the high twenties near 10,000'. Winds will be light (around 10 mph) and erratic, blowing from almost all directions today. As the "storm system that wasn't" moves east this evening, high pressure will again dominate the area. Next week looks to be all high pressure too. Yet another splitting storm moves in off the coast at the end of next week, but it will likely track well away from the Uintas. Looks like Southern Utah is the place to go for powder riding at the moment......


GENERAL ANNOUNCEMENTS

The information in this advisory expires 24 hours after the date and time posted, but will be updated by 7:00 AM Wednesday February 10th, 2010.

If you’re getting out and about and trigger an avalanche or see anything interesting please drop us an email at craig@utahavalanchecenter.org or call 801-231-2170


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.