Salt Lake

Problemi valanghivi

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Likely

  Dimensione

  2

  Strong northwest winds are blowing at speeds of 15-25 mph, with gusts into the 30s this morning. The wind also blows across the low elevations, with gusts into the 20s and 30s at 8,000'. This wind will indeed create new shallow soft slabs of wind-drifted snow. The unfortunate news is we've seen wind over the past 48 hours from all directions, and now the old hard slabs of wind-drifted snow will be covered, making it more challenging to see.

  If the snow is pillowy or rounded, you've likely found a new drift of wind-blown snow. If the snow is hard and hollow-sounding, you likely found a hard drift of wind-blown snow. I would expect wind-drifted snow on all aspects and elevations today.

  It's possible these drifts break to the old snow surface, as many observers noted the old snow surface becoming loose and faceted from the past few days of clear and cold weather. Any wind-drifted snow avalanche can also step down to deeper weaker layers on terrain facing west to north to east at the mid and upper elevations (see PWL below).

  Photo: Showing a wind-drifted snow avalanche (Kelly).

• 

  Storm Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Possible

  Dimensione

  2

  This avalanche problem will depend on how much new snow falls and at what rate. Currently, 2-7 inches of new snow have already fallen, and I would expect new snow soft slabs and dry-loose avalanches as the snow accumulates.

  In southerly-facing terrain, this new snow will fall on slick crusts, and avalanches could run fast and far. On shady slopes, the old snow surface was slightly faceted, and we may see a new snow soft slab avalanche fail at this interface. Use slope cuts and shovel tilt tests to see how the new snow behaves.

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Likely

  Dimensione

  3

  The persistent weak layer (PWL) slowly continues to gain strength, and it is getting more difficult to trigger avalanches. Although the last reported avalanche failing on the PWL was on Tuesday on Cardiac Ridge, we continue to hear reports of collapsing on the PWL, and snow safety teams at nearby resorts are still getting avalanches 2-4 feet deep. The type of terrain you are more likely to trigger an avalanche failing on the PWL is thinner snowpack areas such as:

  • Mid-elevations (particularly between 8,000 - 9,000') where there is less snow.
  • Steep, rocky areas.
  • Slopes that have already avalanched (aka "repeater" slopes) and have partially filled in.

  If you trigger an avalanche in one of these thinner snowpack areas, it could propagate widely and up to 5 feet deep. These are unsurvivable avalanches.