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

Saturday, February 10, 2007 7:30 am
Good morning, this is Evelyn Lees with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Saturday, February 10, 2007 and it’s 7:30 in the morning.

We have a new look to our avalanche advisory thanks to the design work by Jim Conway and the back-end programming by Brett Kobernik. We still have a few additions and changes to come. We also have a new Media Page to communicate present and future avalanche danger ratings.

Current Conditions:

A weak warm front moved through just before dawn, bringing cloudy skies and a trace to an inch of snow to the mountains, mostly north of I-80. Winds are from the west southwest, generally in the 5 to 10 mph range, with a few of the most exposed locations having overnight averages of 15 to 30 mph. Temperatures continue to be unseasonably warm, in the mid 20’s at 10,000’, with a band of above freezing temperatures between about 6,500’ to 8,000’. The old snow surface mostly consists of crusts, ranging from thin zipper crusts, to breakable to icy hard.

Snowpack and Avalanche Conditions:

This will be a weekend of increasing avalanche danger, and the insightful Tom Kimbrough always felt periods of rising avalanche danger were some of the trickiest and most dangerous times for backcountry travelers. This winter’s “powder drought” and unusually weak, variable snowpack will make it doubly hard to evaluate the changing conditions.

Yesterday, 4 small slides were triggered in the Provo area mountains, including a small 3” deep hard slab 8 feet wide and two similarly small soft wind drifts, all breaking on super weak facets and a facet sluff. Many locations have a similar snow pack, with a thin crust precariously balanced on top of ridiculously weak facets. Today, it will be possible to trigger comparable slides – loose sluffs in the facets, hard crusts, and old wind drifts - in isolated areas. Remember, the weak faceted snow exists on just about every aspect, every elevation, either at the surface or shallowly buried beneath thin crusts or old hard wind drifts, so any slopes of about 35 degrees or steeper should be approached with caution. In areas with the hard drifts or crusts, these slides can be triggered remotely or will often break out above you, which means even these 4” deep slides will knock you off balance and have the potential to take you for a ride in steep terrain. Once a slide starts, it has the potential to break into deeper layers, becoming wider or gouging down into the loose, sandbox snow. The weakest snow is on northerly through southeasterly facing slopes, and in the shallower snowpack areas, which are most widespread, but certainly not limited, to the Park City ridgeline, Western Uinta and Provo area mountains. The ongoing warm temperatures and possible rain will continue the chance of triggered wet sluffs or even a wet slabs today.

Bottom Line for the Salt Lake, Park City, Provo and Ogden area mountains:

This will be a weekend of increasing avalanche danger. This morning, there is a MODERATE avalanche danger on all slopes approaching 35 degrees or steeper, especially those with fresh or old deposits of wind drifted snow and the low to mid elevations due to warm temperatures. The avalanche danger will increase to CONSIDERABLE this afternoon or evening as soon as additional snow or rain starts to fall, rising fastest on slopes where the southwesterly winds drift the snow.

Mountain Weather:

A moist southwesterly flow will bring a series of weather disturbances across Utah through the weekend. This morning’s disturbance is rapidly moving east, and there should be a break for most of the day, with partly to mostly cloudy skies and only a few light snow flurries. Snow will redevelop late this afternoon, with 1 to 3” of damp snow possible by evening. The rain/snow line will be around 8,000’. Temperatures today will be in the upper 20’s at 10,000’ and the upper 30’s at 8,000’. Winds will be from the west southwest, in the 10 to 20 mph range, increasing this afternoon into the 15 to 25 mph range across the highest peaks, with gusts in the 30’s. Snow tonight, with 2 to 6” possible, moderate westerly winds and temperatures cooling slightly into the mid 20’s. Periods of snow will continue through Monday morning.

Announcements:

Yesterday, the Wasatch Powderbird Guides did not fly, and in the unlikely event they fly today, they will be in Cardiff, Days, Silver, White Pine, American Fork and Snake Creek. With questions regarding their areas of operation call 742-2800.

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

UDOT highway avalanche control work info can be found HERE or by calling (801) 975-4838.

Our statewide tollfree line is 1-888-999-4019 (early morning, 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.

Drew Hardesty will update this advisory by 7:30 on Sunday morning, and thanks for calling.