Salt Lake Avalanche Advisory

Forecaster: Bruce Tremper

SPECIAL ANNOUNCEMENT

For your viewing pleasure, we've been glued to our computer screens for the past couple days admiring the huge, deep-slab in the backcountry south of Bridger Bowl Ski Area near Bozeman, Montana. This occurred a couple days ago and it took out many tracks. It's a good reminder to watch the "social proof" heuristic, or what I call the "herding instinct."

Link 1,

Video

BOTTOM LINE

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


Danger Rose Tutorial

There is a CONSIDERABLE avalanche danger on mid elevation, northwest, north through east facing slopes with pockets of CONSIDERABLE on other slopes. There is a MODERATE danger on south and southwest facing slopes.

CURRENT CONDITIONS

A light dusting of new snow fell yesterday, giving us a few inches of fluff on the shady slopes and there are some challenging sun crusts on all the sunny aspects. Snow is falling this morning and we're expecting a couple more inches.

RECENT ACTIVITY

We will likely remember the 09-10 season as the year of living dangerously. The saga continues...by my count, yesterday there were 8 skier or boarder triggered avalanches in the backcountry with 3 people caught and 2 partial burials. Check our astoundingly popular, Current Conditions section for details. Also by my count--well never mind--I can't count that high. There has been about 12 bazillion, human-triggered avalanches in the past 10 days--not to mention the rest of the winter. All these avalanches are relatively shallow, soft slabs of about a foot deep sliding on a buried layer of surface hoar that formed a week and a half ago on snow snow surface and was then buried by new snow.

THREAT #1
WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Buried surface hoar is one of the "persistent" weak layers and now you can see why. A week and a half after it formed on the snow surface--and buried--it continues to produce avalanches with very little additional loading. It's a tricky one, that wily surface hoar. It's thin, very weak, hard to detect, patchy, and as Canadian forecaster, Clair Isrealson told me once, "it's like your crazy aunt who comes for a visit. It overstays its welcome and you never know when it's going to snap."

A few days ago, it was delightfully sensitive; you just had to sneeze on a 30 degree slope and you got instant feedback. Now, as both the weak layer and the slab gains strength, it allows you to get out onto it before it shatters. So if anything, it may be more dangerous now than before. And yes, all this stuff is complicated. Last night, it took me 10 minutes to explain our current conditions to my wife, even though she's been my most steady backcountry skiing partner for nearly two decades. The bottom line is to continue to watch your slope steepness. I have not gone over 30 degrees in many weeks. Ihave seen lots of bold lines lately and that kind of dangerous living does not have much of a future.

THREAT #2
WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Deep slabs remain in the back of our minds especially in the thinner snowpack areas. These thinner areas now include many of the avalanche paths that avalanched in January and have been filled back in. This snow that's filled back in has faceted and is quite weak. Depending on the upcoming loading pattern, these paths may be setting up to run again.

MOUNTAIN WEATHER

This weekend's series of storms look disappointing for northern Utah but they should bring a couple feet to the central Utah mountains. In northern Utah, it looks like we will get about three different, weak, pulses of moisture without much wind--all added together might pile up to 8 inches by later on Sunday. Today, we should get about 3 inches with clearing later this afternoon or evening and repeat this pattern for the next 3 days. Temperatures should remain cool to preserve the snow, at least on the shady aspects. Ridge top temperatures should be around 20 degrees with overnight lows in the mid teens.

GENERAL ANNOUNCEMENTS

Please contact Alta Central (801-742-2033) if you trigger a large avalanche in the backcountry, especially if you are adjacent to a ski area, to alert them to the slide and whether anyone is missing or not. Rescue teams can be exposed to significant hazard when responding to avalanches, and do not want to do so when unneeded. Thanks.

Discount Lift tickets: Ski Utah, Backcountry.com, Alta, Deer Valley, Park City, The Canyons, Wolf Mountain, Snowbasin, Beaver Mountain, Brighton, Sundance, and Solitude have donated a limited number of tickets for sale at discounted prices.

Wasatch Powderbird Guides flight plan.

Dawn Patrol Forecast Hotline, updated by 05:30:888-999-4019 option 8.

Daily observations are frequently posted by 10 pm each evening.

Free UAC iPhone app from Canyon Sports.

Subscribe to the daily avalanche advisory e-mail click HERE.

UDOT canyon closures UDOT at (801) 975-4838

We appreciate all your avalanche and snow observations. You can also call us at 801-524-5304 or 800-662-4140, or email to uac@utahavalanchecenter.org

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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.

We will update this forecast tomorrow morning. Thanks for calling.

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.