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

Monday, December 03, 2007 7:30 am
Good morning, this is Drew Hardesty with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Monday, December 03, 2007 and it’s about 7:30 am.

Current Conditions:

This morning, skies are mostly clear but we’ll start to see increasing clouds moving through the current dirty ridge of high pressure. Mountain temperatures skyrocketed from yesterday’s single digits and are now in the upper twenties at most locations. The greatest gains are found along the highest ridgelines as a temporary inversion kicked in. Southwest to westerly winds increased and are blowing 15-20mph in the central Wasatch and perhaps twice that north of I-80.

Riding conditions are greatly improved, though you’ll need to look for terrain above, say, 9500’-10,000’ on the shady aspects to find enough coverage. Snowmachines will want to remain on the snow-packed roads.

Avalanche Discussion:

While the backcountry skiing and riding is not interesting, the snowpack structure and associated avalanche problems are. Backcountry skiers again unintentionally triggered three more avalanches in mid and upper Little Cottonwood Canyon. In the side country of mid-LCC, an experienced skier had a 16” deep and 75’ wide avalanche pull out above him, but he fortunately was able to ski off the slab. Not long afterward and not too far away, another backcountry skier wasn’t so lucky. Traversing on an uptrack, he reportedly heard a thunderclap collapse of the weak depth hoar below, ripping out a 1-2’ deep and 80’ wide hard slab above him, carrying him 150’ down the slope, uninjured. Both slides pulled out above about 10,300’ with the first on a more northerly slope, and the second having a more easterly component – with the slab collapsing the remains of an eroding melt freeze crust. On the other side of the road, a skier walking the ridge above Days Fork remotely triggered a popular north-facing run 18” deep and 200’ wide. Ski area avalanche control work continues to produce excellent feedback on the lingering instabilities. Bruce and Brett’s field day galleries can be found on our photos page here.

As I said, the snow is interesting. For the beginner, or lazy backcountry recreationist, all the signs are present: avalanches, cracking, collapsing, and now rapid warming and wind drifting. Those with the inclination to pull out their shovels and snow-geek tools will be rewarded with the beautiful crystalline structure of the weak faceted snow and rewarded with stability test results that are very representative of the current issues, rather than variable and inconclusive, as they sometimes are.

Today’s prevailing problems will continue to be centered on the persistent slab instabilities on the steep shady terrain where remotely triggered slides remain possible. This makes for even more difficult route finding as avalanches may pull out above, below, or adjacent to you. Put only one person on the slope at a time, and if trouble is found, start your search at the last seen point, and pull out the first aid kit as they will no doubt suffer from traumatic injuries bouncing off thinly buried rocks, stumps, and deadfall.

Bottom Line:

Salt Lake and Provo area mountains: The avalanche danger remains MODERATE on northwest, north and northeast facing slopes steeper than about 35 degrees above about 9,000’ in elevation. Human triggered avalanches, including the potential to trigger slides from a distance, remain very possible. Shallow, sensitive new wind drifts will pocket the high, lee terrain. Avoid any smooth, pillowy pockets on the steeper slopes.

Park City Ridgeline and upper Mill Creek: Other than the shallow drifting up high, the danger is generally LOW with so little pre-existing snow.

Ogden area mountains: The danger is generally LOW with so little pre-existing snow. A few shallow drifts are likely in the high terrain, but it’s difficult still for most folks to access the high country.

Mountain Weather:

Moisture will start to stream through the current shortwave ridge and skies will turn mostly cloudy by the afternoon. Winds will blow 20-30mph from the west while temperatures continue to hike toward the upper 30’s at 10,000’ and mid 40’s at 8000’. I’m optimistic with a couple of weaker cold fronts over the next couple of days which could add up to 10” in areas favored by a west to northwest flow. A much warmer, wetter, and windier storm looks to be on tap Friday into Saturday, followed by a strong cold front perhaps Sunday into Monday. Stay tuned.

Announcements:

For an avalanche education class list, click HERE.

If you want to get this avalanche advisory e-mailed to you daily click HERE.

The UAC has job openings. Click HERE for info.

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 our classic text advisory click HERE.

If you’re getting out and see anything we should know about please let us know. You can leave 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.

Brett Kobernik will update this advisory by 7:30 Tuesday morning.