Wasatch Cache National Forest
In partnership with: Utah Division of State Parks and Recreation, The Friends of the Utah Avalanche Center, Utah Department of Emergency Services and Homeland Security and Salt Lake County.

“keeping you on top”

AVALANCHE ADVISORY

Friday, December 15, 2006 7:30 am
Good morning, this is Brett Kobernik with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Friday, December 15, 2006 and it’s 7:30 in the morning.

Current Conditions:

Under cloudy skies 9000 foot temperatures at many locations are above freezing with ridgetop southwesterly winds in the 10 to 20mph range gusting into the 20s and 30s with the most exposed locations having gusts into the 40s and 50s. Precipitation over the last 24 hours included snow flurries at the higher elevations with the rain level between 8000 and 9000 feet. Very little precipitation fell from the Provo mountains north through Farmington Canyon but the Ogden area mountains did receive close to a half inch of water weight in the last 24 hours.

Snowpack and Avalanche Conditions:

As far as the snowpack is concerned we can divide things up by region fairly easy. The Provo mountains, Park City mountains, Mill Creek Canyon and Bountiful mountains have a thin weak snowpack but haven’t received enough snow to increase the danger much. The upper Cottonwoods have a deeper snowpack that does contain some weak snow but didn’t receive enough snow to produce significant avalanches except a few stubborn wind slabs at the higher elevations. The Ogden area mountains had a thin weak snowpack and have received enough of a load to produce a dense slab that has overloaded the weak snow resulting in some natural avalanches. The majority of these were in the upper elevations where winds helped to build a thicker slab but at least one was around 7500’ in a wind sheltered area. (Click HERE for some observations) These avalanches ranged from 1-3 feet deep, 50 to 75 feet wide with the biggest one running around 400 feet vertical distance. These were on north through east facing aspects. The warm temperatures are currently adding to the avalanche danger but after things cool off the snow should lock up and take care of many of our problems with the deeper faceted snow.

For today we have a few things to keep in mind. First are the continued warm temperatures. Many lower elevation slopes have a very damp, unconsolidated snowpack where we may see activity in the form of loose snow avalanching and the possibility of a slab avalanche as well. Stay out of gully bottoms and other terrain traps if you are traveling in areas that have damp snow.

We also need to pay attention to areas where the recent slab may break into faceted layers that formed in early December as well as in November. This is most common in the northern mountains from around Ogden north but be aware of any slope that has a recent layer of thick snow that is over weak sugary snow. Watch for collapsing which would indicate this set up exists. This is less prevalent in the Cottonwoods but you may find a few areas along the ridges where you may get a fresh drift to crack out.

Bottom Line:

For the Ogden area mountains the avalanche danger is MODERATE on slopes steeper then around 35 degrees especially in upper elevations that have recent deposits of wind drifted snow. Avalanches may break into older weak snow that would produce a sizeable slide.

For the Salt Lake, Park City and Provo area mountains the avalanche danger is MODERATE for upper elevation north through east facing slopes steeper then 35 degrees with recent deposits of wind drifted snow as well as steeper lower elevation slopes where the snowpack is damp. Mid elevation slopes less steep then 35 degrees have a generally LOW danger.

Mountain Weather:

Today we’ll see mostly cloudy skies. Ridgetop temperatures should start to cool off around noon and ridgetop winds will blow in the 10 to 20mph range gusting to around 30 and into the 50s at the most exposed locations. A few snow flurries are possible this afternoon then snow should start tonight. Weather models are still having trouble pinning down a good solution to this storm but confidence is fairly high that we’ll receive an inch of water that would translate into around a foot of snow by Saturday. Mostly cloudy skies with snow showers and cooler temperatures will remain through Sunday.

Announcements:

Wasatch Powderbird Guides ski season starts today but they will not fly due to weather and snow conditions.

Listen to the advisory. Try our new streaming audio or podcasts

Our new, state wide tollfree hotline is 1-888-999-4019.
(For early morning detailed avalanche activity report hit option 8)

For a list of avalanche classes, click HERE

For our classic text advisory click HERE.

To sign up for automated e-mails of our graphical advisory click HERE

We appreciate any snowpack and avalanche observations you have, so please leave us a message at (801) 524-5304 or 1-800-662-4140, or email us at [email protected]. (Fax 801-524-6301)

The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.

Evelyn Lees will update this advisory by 7:30 on Saturday morning.