Ogden Avalanche Advisory

Forecaster: Drew Hardesty


I've issued a Special Avalanche Advisory for the mountains of northern and central Utah, to include the Bear River Range and the Western Uintas. Strong winds and additional snowfall will create dangerous and widespread avalanche conditions. Human triggered avalanches are likely; natural avalanches possible. Backcountry travel requires cautious route-finding and conservative decision making.

There is a Women’s Snow and Avalanche round table tonight, Tuesday Feb 21,at the Sandy REI, discussing current snow and avalanche conditions and careers in the snow and avalanche industry. Please register at REI HERE.


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

Danger Rose Tutorial

The danger will be on the rise. A full CONSIDERABLE danger exists in all wind drifted terrain and more pronounced on steep north through southeast facing slopes today. Human triggered avalanches are likely with natural avalanches possible. Cautious route-finding and conservative decision making is required for backcountry travel today.


The next series of storms are upon us - the mountains have already picked up 2-5" of higher density snow across the ranges of northern Utah. The winds are the kicker - as anticipated, they're blowing 20-25mph from the west...with the most exposed anemometers punished by 40-45mph winds and gusts into the 50s...Temperatures are in the teens.


Most of the avalanches triggered yesterday and the day before were in the new snow – sluffs and shallow new wind slabs up to a foot deep and 50’ wide or so. This type of avalanche is easily mitigated or avoided and is what I would term “Manageable”. I wouldn’t call them harmless, but – “more forgiving” unless you’re pushed into or through terrain traps. Avalanches of this type (northerly through easterly above 9400’) – most running on Saturday’s weak snow surface of either recrystallized faceted snow or surface hoar triggered by backcountry skiers included:

· Upper Days Fork (at least three) up to a foot deep and 30’ wide (1st pic - Mark White)

· Keyhole into Cardiff Fork – 8-10” deep and 20’ wide

· LCC UDOT Indicator Slope – 6-16” deep and 40’ wide

· West Bowl of Silver Fork – 3-12” deep and 50’ wide (2nd pic - Jake Hutchinson)

Others – the Outliers (the Low Probability – High Consequence situation we’ve had for more than a month) will kill you…or result in significant injuries or deep burial. The Black Sheep, or Black Swan – outside of our day to day pattern recognition. Three significant Black Swans over the past two days

· A single explosive thrown in the uncompacted/unskiied terrain along the Pinecone ridge of the Park City Mountain Resort triggered an adjacent avalanche path 2-3’ deep and 275’ wide. It pulled out to near the ground, leaving a black hole in the intact snow where the charge detonated. (This mind you, a single 2 pounder surface shot). (PCMR photo, below)

· A snowmobiler in the Franklin Basin terrain (in the Logan forecast area just north of the Idaho border) unintentionally triggered a deep slab 3.5’ deep and 60’ wide on a steep east facing aspect at 9000’. You can watch the rider abandon his sled, grab a tree and hold on, the hard slab washing by into the flats. (Observation/video – Warning! PG rating for language – that is – an authentic video/not a scripted made for tv gig)

· Kobernik and Meisenheimer found a 1’ deep and 200’ wide hard slab triggered on Sunday by a snowmobiler in the Ant Knolls area of American Fork/above Midway. It was on a southeast facing slope at 9500’, collapsing a couple inch thick melt freeze crust in the process. (Kobernik photo below)


      Over the next 24 hours.

Whereas yesterday's new soft slabs and wind drifts were pockety, today's will be significantly more widespread with more propagation potential (that is, they will break out wider and deeper). Strong winds and higher density snow over Sunday's low density smoke - it's not rocket science. It's also quite likely that they can be triggered on approach, from a ridgeline, or from adjacent terrain. The new wind slabs will likely fail on Saturday's weak snow surface of surface hoar feathers or recrystallized snow and may step down further to slow-to-heal weaknesses from the end of the first week of February. Manageable yesterday, decidedly less so today. Caution required.

Particular attention should be paid to the lower elevation terrain with weak faceted snow and/or surface hoar over a slick bed surface as well...


      Over the next 24 hours.

Any avalanche triggered may step down into the older snow layering resulting in a much more dangerous slide.


We'll have periods of snow through the day that may add up to 8" or so in favored terrain. Densities will be higher than the last storm - in the 8-10% range with areas north of I-80 on the higher end of the stick (particularly Logan). Winds will remain strong from the west northwest blowing 35-40mph along the ridgelines. A cold front arrives early Thursday bringing additional snow. Friday offers some clearing with another perhaps significant storm on tap for the weekend.


If you trigger an avalanche in the backcountry - especially if you are adjacent to a ski area – please call the following teams 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.

Salt Lake – Alta Central (801-742-2033)

Ogden – Snowbasin Patrol Dispatch (801-620-1017)

Provo – Sundance Patrol Dispatch (801-223-4150)

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

Twitter Updates for your mobile phone http://utahavalanchecenter.org/twitter)

Daily observations are frequently posted by 10 pm each evening.

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

UDOT canyon closures UDOT at (801) 975-4838

Wasatch Powderbird Guides does daily updates about where they'll be operating on this blog http://powderbird.blogspot.com/ .

You have the opportunity to participate in the creation of our own community avalanche advisory by submitting avalanche and snow observations. You can also call us at 801-524-5304 or 800-662-4140, or email by clicking HERE

Donate to your favorite non-profit –The Friends of the Utah Avalanche Center. The UAC depends on contributions from users like you to support our work.

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.