Utah Avalanche Bulletin

This bulletin is from the UAC, which is part of the US Forest Service.

Utah Avalanche Center (UAC) Advisory

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

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Monday, February 8th 2010

Current Conditions:

Skies are clear, winds are light, and temps are in the single digits to low teens. Riding conditions are excellent in the sheltered terrain and sun crusted on the east to south to westerly facing slopes.

Recent Activity:

· per-sis-tent, adj. 1. lasting or enduring. 2. existing for a long or longer than usual time. 3. continuing without change in function or structure.

A rough day in the backcountry yesterday. Multiple dangerous slides triggered with many close calls, including one that required a helicopter evacuation due to reported extensively fractured legs. We'll start with that one.

· Hats off to members of the SL county SAR, WBR, AirMED, and others for the rescue. An experienced skier triggered a 2-4' deep 600' wide hard slab on a steep rocky slope half-way down Wilson Peak northwest into Alexander Basin yesterday. He hit a tree sustaining numerous severe injuries, but kept him from going for the full 1000' ride and potential burial.

· In the next drainage to the west, a very experienced backcountry skier triggered a deep slab a few turns down the main face of Gobbler's Knob. It was on a steep northwest facing slope at 9500', pulling out 2-4' deep and 400' wide, running over 2000'. He was able to grab a tree to slow down, reportedly dislocated his shoulder while trying to arrest on the bed surface and washed 1500' down the slope. He was able to get out on his own.

· Gobbler's was the scene of another avalanche. Another very experienced party unintentionally triggered a 2-3' deep and 75' wide hard slab on a steep northwest facing slope at 9300'. It was the third skier on the run, taking out previously laid tracks.

· Witnesses standing at the top of Main Days watched a lone skier trigger a slab on a hanging snowfield above the cliffband of what is called Jaws, a steep couloir in Upper Days. It looks to be 1-2' deep and perhaps 50' wide with debris spilling over the cliffs below.

· In Argenta, a notorious slide path above BCC, a snow-shoer collapsed a piece of snow at 9700'. It cracked 10' wide, likely provoking the facets buried a few feet below.

· In the Bountiful Peak area, Bruce's party triggered a small soft slab on surface hoar a foot deep and 20' wide on a 29 degree slope. It ran an estimated 60' on the gentle north facing slope at 8000'.

The most dangerous snow pack issue is the loose, weak snow is found near the base of the pack. Both the slab above and the weak layer are slowly strengthening, but there are still places where one can trigger a 2 to 4' deep slide near the ground. The most suspect slopes face northwest through east at the mid and upper elevations. A slide would most likely be triggered in a shallow, rocky spot, such as a steep break over, and then propagate.

Very, very experienced people are being fooled by this notoriously tricky snowpack. Professionals. People with 30 years in the business.

Terrain is your friend. The riding is quite good on the gentler slopes.

Ensure that the slope you're on is not attached to or under a steeper avalanche path nearby. Unsure? Get educated - take an avalanche class - and come back another time. This problem is not going away anytime soon.

Watch for some dampening of the snow surface with daytime heating.

Expect some human triggered sluffing.

Bottom Line:

An overall danger exists in the Wasatch. Pockets of danger dot the landscape on the steeper northwest through north through northeast facing slopes at the mid and upper elevations.

Clearly, it's still possible to trigger dangerous and persistent deep hard slabs 2-4' deep. Death or serious injury is likely.

Ogden area mountains:

A TRICKY danger exists at the mid and low elevations with the lingering surface hoar from late January. My own party triggered a loud collapse yesterday on the 15mm feathers while approaching an older natural.

Mountain Weather:

We'll have mostly sunny skies, light northeasterly winds, and temps in the low teens at 10,000' and mid-twenties at 8000'. Another storm dives south of us by mid-week.

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The USFS posts some additional information through the season:

• Snow Profiles
• Photos
• List of Avalanches

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