Avalanche forecast

Salt Lake

Utah Avalanche Center
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Avalanche danger

  • Alpine
  • Treeline
  • Below treeline
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Out of date — this forecast expired 8 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

There is a CONSIDERABLE danger for slab avalanches failing on weak, sugary, snow 2-3' feet deep. This problem is found on mid & upper elevation slopes that face northwest, north, northeast and east. Don't be fooled by the sunshine and beautiful powder snow, these are the exact conditions that lead to avalanche accidents and fatalities. Dangerous avalanche conditions do exist, careful snowpack evaluation, cautious route-finding and conservative decision making is essential today.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Yesterday there was a wind gust reported at 102 mph at upper elevations. Wind along with 20-30" of new snow has created many drifts of wind blown snow scattered across the terrain. The good news: wind drifts are easy to spot by their rounded appearance and they tend to stabilize quickly. The bad news: is that with such strong winds you can expect cross loading at all mid and upper elevations and drifts that have formed in odd places as well, like gullies and mid slope break overs. Avoid being on any steep slopes that's been wind loaded.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    3

    We have a CONSIDERABLE danger for slab avalanches. Very weak faceted snow has become overloaded by the strong winds and heavy snowfall. This weak, sugary, faceted snow is found on mid elevation, northwest, north, northeast, and east facing terrain. As well as the upper elevation west through southeast facing terrain. These are the slopes I would avoid for the next couple of days. Don't be fooled by the sunshine and beautiful powder snow, these are the exact conditions that lead to avalanche accidents and fatalities. The slab avalanche you trigger has the potential to be 2-3' deep and several hundred feet wide. This is the type of avalanche that will kill you! Any steep slope with old faceted snow should be off limits.

    Avalanches can be triggered from a distance today and from adjacent terrain. Avoid walking in runout zones and being underneath anything steep in the terrain described by the locator rose above. Be mindful of anyone below you if you're walking on ridgelines.

    Photo: Trent Meisenheimer. Snowpit from a NE facing slope in upper Little Cottonwood, highlighting the dangerous layer of faceted snow. This photo was taken Friday 23rd before we added another 1-2' feet of heavy snow.

Recent Activity

Strong winds and heavy snowfall have overloaded our snowpack, leading to a natural and human triggered avalanche cycle yesterday. Numerous avalanches were reported from both backcountry travelers as well as snow safety teams. The avalanches were up to size 3 on the destructive scale (meaning it could bury and destroy a car, damage a truck, destroy small buildings or break trees.) Many size 2 avalanches were also reported and these are large enough to bury and kill a person.

These avalanches failed on a layer of very weak faceted snow that formed over the month of November due to cold clear nights. These avalanches were up to 2-3' deep, 100'-250' wide, running into the flats. Here is the link to all current backcountry observations. HERE

Photo: Greg Gagne, Slab avalanche on Rocky Point in upper Little Cottonwood Canyon.

Snow and Weather

For today we should see party cloudy skies and cold temperatures. Winds have backed off considerably and are currently blowing 5-10 mph across the highest terrain. Temperatures have plummeted into the single digits at upper elevations and are in the mid teens at many of the mid canyon trailheads. The Thanksgiving storm was just what we needed and storm totals are as follows:

  • Upper LCC: 20-24" of snow (1.50"-2.05" H20)
  • Upper BCC: 25-30" of snow (1.50"-3.21" H20)
  • Provo area: 17.5-24" of snow (2.7"-3.23"H20)
  • Ogden area: 20-24" of snow (1.50-2.93" H20)
  • Park City: 16-20" of snow (1.50"-2.0" H20) )

Additional Info

High pressure will take hold for the next few days leading to clear skies and a warming trend. There does look like another storm on the horizon for late Wednesday into Thursday as the polar jet sets up on a westerly flow overhead. Stay tuned.

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