Skyline Avalanche Advisory

Forecaster: Grant Helgeson

BOTTOM LINE

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


Danger Rose Tutorial

On Friday, the avalanche danger is mostly Level 1 (Low) with pockets of Level 2 (Moderate). Natural avalanches are unlikely, but human triggered slab avalanches are possible, especially in locations where you find yourself breaking through the rain crust.

On Saturday, the same persistent slab danger exists along with a Level 2 (Moderate) avalanche danger in the form of a wind slab. The wind slab danger may jump to Level 3 (Considerable) Saturday afternoon as winds gust into the 40 mph range at upper elevations.


CURRENT CONDITIONS

It's currently "dust on crust" out there. A strong rain crust was formed last weekend on all aspects & elevations. There are about 3" of powder snow on top of the crust. Needless to say, side hilling will be a bit of a challenge this weekend.


RECENT ACTIVITY

Yesterday I observed quite a bit of activity from last Sunday's warm temps and rain, but that's ancient history now. No recent activity reported or observed.


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Here's a simplified version of the current snowpack structure: Stout rain crust on top, buried surface hoar 5” - 10" below. Yes, the rain crust is quite strong and supportable, and for the most part, it's keeping the surface hoar from ever feeling our weight. But, surface hoar only needs a hair trigger to activate, and I'm not 100% certain that the rain crust will keep us out of the surface hoar everywhere. For the most part, you should be good to go, but, be aware; there is still a small chance of triggering a slab avalanche this weekend. If you get to a place where you start breaking through the crust, relocate to an area with a more supportable crust.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 48 hours.

Wind slabs should not be an issue on Friday.

But, as we move into the weekend, the ingredients for wind slab start to come together. A small short wave storm makes its way south this evening, continuing into Saturday. Snow totals aren't very impressive with this one, only 3" - 7". But, there is plenty of wind tagging along. We can expect sustained winds in the 20 – 25 mph range with gusts as high as 40 mph. The new snow will quickly be blown into sensitive wind slabs on slopes that face N, NE, E & SE. Avoid steep open terrain Saturday once the wind starts cranking.


MOUNTAIN WEATHER

Today we will have mostly cloudy skies with a high in the upper 20's. After sunset a small disturbance moves in bringing light snow showers that will continue into Saturday. Saturday will dawn snowy & windy with a high near 25. Snow tapers off Saturday night, skies clear & the temperature falls into the teens. Sunday brings partly sunny skies with a high near 29.


GENERAL ANNOUNCEMENTS

See or trigger an avalanche? I'd like to hear about it! You can reach me on my cell phone: 801-824-0305 or shoot me an email: grant (at) utahavalanchecenter (dot) org Observers may choose to remain anonymous if they wish.

Click here for a refresher on the Avalanche Danger Scale.

Click here for a review on the Danger Rose.

This forecast will be updated by 7:00am Friday January 28th.


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.