Avalanche forecast

Logan

Utah Avalanche Center
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Avalanche danger

  • Alpine
  • Treeline
  • Below treeline
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Highlights

Dangerous natural and human triggered avalanches are likely and the danger is HIGH in the backcountry. People are likely to trigger soft slab avalanches of storm snow up to 3 feet thick as well as loose avalanches entraining significant volumes of powder snow. Most likely during periods of particularly heavy snowfall and drifting, long running natural avalanches could run well out onto the flats or down into lower elevation bench areas.

  • Avoid avalanche runouts and stay off and out from under slopes steeper than about 30°

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2

    While the snow is probably pretty unstable this morning, having just fallen, it should gain stability pretty quickly in most places. Since cold weather is in the forecast, it's likely that the powder will stay really good for a while, and it'll be worth waiting for a little while for it to stabilize.

    • Human triggered and natural avalanches of storm snow are likely today. Both are even more likely during periods of particularly heavy snowfall and drifting.
    • There are areas where weak surface snow was buried and preserved by light powder last week, and this weekend's copious new snow will likely create potential for soft slab avalanches, especially in areas where the fresh snow is drifted onto slopes steeper than about 30°.
    • Loose avalanches entraining storm snow are likely on very steep slopes at all elevations. On sustained slopes these can pick up speed and volume pretty quickly. Generally, you should stay out from under your partners and other parties and avoid very steep terrain where you could be swept into trees, gullies or other terrain traps. But today, you should just avoid travel on and under slopes steeper than 30°.

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2

    People are likely trigger soft slabs of wind drifted storm snow up to a couple feet thick in drifted terrain. Harder wind slabs from last week will be hidden by the fresh powder, but some could still be sensitive to human triggers. Sustained winds from the west enlarged cornices and built fresh wind slabs. Some of these probably formed on weak surface snow that was preserved by a couple inches of powder last week and could remain pretty touchy.

    • Avoid corniced slopes and stiffer drifts on steep slopes near ridges and in and around terrain features like under cliff bands, sub-ridges, mid-slope break-overs, and gully walls..
    • Even a small wind slab avalanche can have large consequences if you get swept into trees or other terrain traps.

Avalanche Warning

  • In effect from 6am MST this morning to 6am MST Monday.
  • For the Wellsville and Bear River Mountains of Northern Utah and Southeast Idaho.
  • Recent very heavy snowfall and drifting created widespread areas of unstable snow. Both long running natural avalanches and dangerous human triggered avalanches are likely.
  • Stay off of and out from under backcountry slopes steeper than 30 degrees.

Recent Activity

There were two dozen human triggered avalanches reported to the UAC from yesterday in the Wasatch Mountains, including a few people caught and caried, and at least one injured. A sure sign of potential instability in the backcountry is recent avalanche activity, and while most people did not venture into avalanche terrain yesterday, conditions were pretty active Friday afternoon in the Logan Zone.

  • A few small natural avalanches of wind drifted storm snow hit the highway in the Dugway section of Logan Canyon yesterday afternoon causing a brief closure so crews could clean the soft debris off the road.
  • A skier triggered a small avalanche of wind drifted snow at 6700' in elevation on a south facing slope across from the Franklin Basin overflow parking lot.
  • Skiers report cracking and extensive drifting in lower elevation terrain adjacent to Cherry Peak Find a list of all observations & avalanches from across Utah HERE.

Snow and Weather

People should avoid travel in backcountry avalanche terrain today, which means stay off and out from under slopes steeper than about 30°. We expect the heavy snowfall to decrease and become showery this morning, and be mostly gone by afternoon. This is the end of the storm and probably near the peak of instability, with natural avalanches probably ongoing in the mountains. The fresh snow is unstable this morning but it will probably gain stability pretty quickly as snowfall and drifting cease.

Better wait till tomorrow and many cold days to come to enjoy the deep powder on slopes steeper than 30° in the backcountry. I have been unable to read snow depths well but there is probably at least three feet of new snow at upper elevations from this storm so far.

Heavy snow continues to fall this morning, with 11 inches as seen on the lit Cherry Peak Snow Stake. The Tony Grove Snotel at 8400' reports 3.9 inches of Snow Water Equivalent. The temperature is 17° F, and there now well over 100 inches of total snow. The CSI Logan Peak weather station at 9700' is showing winds blowing from the west-northwest this morning around 18 mph with gusts around 35 mph.

Today snow showers will taper off and it'll be mostly cloudy and cold, with 1 to 3 inches of additional accumulation possible in the morning, temperatures at 8500' will drop to around 5° F and winds blowing from the north-northwest at around 10 mph will create wind chill values around -10° F.

Tonight will be mostly cloudy, with low temperatures around -13° F, and 10 mph winds from the north will bring wind chill values down to around -26° F.

Tomorrow will be mostly sunny and cold, with high temperatures around 10° F, and moderate winds blowing from the northwest creating wind chill values around -29° F.

It looks like the sun will be out but temperatures will stay cold on Tuesday, with gradual warming as the work week progresses and no sign of significant storminess.

General Announcements

  • Please submit your observations from the backcountry HERE.

  • For a list of avalanche classes from the Utah Avalanche Center go HERE
  • For information on where you can ride your sled or snowbike, check out this map of the winter travel plan for the Logan and Ogden Ranger Districts HERE, and a close up of the Tony Grove and Franklin Basin Areas HERE.

This forecast is from the U.S.D.A. Forest Service, which is solely responsible for its content. This forecast describes general avalanche conditions and local variations always occur.

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