Logan Avalanche Advisory

Forecaster: Evelyn Lees

SPECIAL ANNOUNCEMENT

A Special Avalanche Advisory has been issued for the mountains of northern and central Utah and the western Uintas. Dangerous avalanche conditions will persist today due to recent heavy snow and strong winds. Backcountry travelers should avoid travel on and below steep slopes.

BOTTOM LINE

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


Danger Rose Tutorial

The avalanche danger is CONSIDERABLE in all steep, wind drifted terrain and for cornice failure. CONSIDERABLE means natural avalanches are possible, and human triggered slides likely. Smaller slides have the potential to step down to deeper weak layers, resulting in a deep, dangerous slide. If the snow on steep, sunny slopes heats up, the danger on these slopes will rapidly increase. Out of the wind affected terrain, the avalanche danger is MODERATE on slopes less steep than about 35 degrees.

Considerable avalanche danger ratings are tough because they put a lot of the assessment burden on YOU, the backcountry traveler. (Dave Medara) Training and experience are essential today. If uncomfortable with snowpack stability evaluation or conservative decision making, avoid avalanche terrain or head to the resorts.

CURRENT CONDITIONS

The storm is over! Skies are mostly clear, temperatures are in the teens in the Logan area mountains, and the northwesterly winds are about 15 to 20 mph. Else where in the range, the most exposed peaks are averaging 15 to 25 mph, with gusts in the 30’s. In the past few days, about 2 to 3 feet of snow fell in the Logan area mountains, and since the start of the month, mountains locations have roughly received up to 5" of water equivalent. Along the high ridge lines yesterday, the northwesterly winds blasted all day, averaging in the 40’s, with gusts in the 60’s and 70’s.

RECENT ACTIVITY

We have no new observations from the Logan area mountains. Continuously steep terrain and large amounts of snow and wind in Little Cottonwood resulted in widespread activity, with both natural and explosive triggered large slides crossing the road, and resort explosive control work releasing medium to very large slides. At other resorts, the very sensitive new snow activity was widespread on all aspects, especially in wind loaded terrain. The 2 to 3’ deep soft slabs were sensitive to both ski cuts and explosives. 3 to 5’ deep slides were released with explosives on the wind loaded ridgelines in the Ogden Area Mountains. A few backcountry observations from mid BCC found good turning on lower angle slopes, with very sensitive cornices and wind drifts.

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

Wind drifted terrain will remain the most likely place to trigger a slide today, and the danger will increase with elevation and wind exposure. The strong northwesterly winds loaded snow onto the east side of the compass, but also cross loaded snow around terrain features on all aspects and elevations, such as mid-slope breakovers and gully walls. Cornices will be very sensitive, and could break back much further than expected, so stay well back from the edges. Remote triggering is a distinct possibility today. Jumping on wind drifted small test slopes will be a great way to start your stability evaluation.

THREAT #2
WHERE PROBABILITY SIZE TREND
      Over the next 12 hours.

There are multiple layers in the upper snow pack, including a couple of dust layers and graupel (pellet snow) layers pooled beneath cliffs and on lower angle terrain. Once snow gets moving, from a cornice drop, new snow sluff or soft slab, or triggered wind drift, there is a chance a slide could break into one of these deeper layers, resulting in a large, dangerous slide.

THREAT #3
WHERE PROBABILITY SIZE TREND
      Over the next 10 hours.

And finally, despite the cool temperatures, the combination of strong sun and no wind may be enough to heat the snow on steep, sunny slopes. If you’re in a place where the snow surface gets warm and damp, it could rapidly become sensitive, and easy to trigger wet loose sluffs, which could in turn trigger larger slab avalanches.

MOUNTAIN WEATHER

High pressure building into the Great Basin will bring a dry, stable air mass with light winds to the mountains. Temperatures will remain cool today, with 10,000’ highs in the mid to upper teens. The northwesterly winds will be in the 0 to 10 mph range, with only a few of the highest peaks gusting into the 30’s. Significant warming will occur tomorrow, Thursday, under clear skies as the flow shifts back to the southwest ahead of the next storm system. A mostly dry cold front will push into northern Utah Thursday night through Friday, bringing cooler temperatures and a slight chance for snow.

GENERAL ANNOUNCEMENTS

The ability to deal with medical emergencies is a vital backcountry travel skill. On April 9-11, Utah Wilderness Safety will be conducting a Wilderness & Remote First Aid course in SLC. As an added bonus, WMS has agreed to donate a percent of the class proceeds to the FUAC. For more details, go to our events calendar or www.utahwildernesssafety.com/FIRST-AID.html.

SLC: 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.

Ogden: Please contact Snowbasin ski patrol (801620-1000/1017) 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.

Provo: Please contact Sundance ski patrol (801 -223-4150) 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 and the local resorts donated lift tickets, with 100% of the proceeds going to the Utah Avalanche Center. To get the last few tickets left for Park City, Beaver Mountain, and Sundance – click here 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 fill out the observation form on our home page.

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.

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.

I 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.