Ogden

Avalanche problems

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  3

  As the name suggests, this layer is persistent and at northerly upper elevations, above 9000', weak faceted snow does still exist at the ground. This layer of old faceted snow has been found near Snowbasin, Powder Mountain, on Ben Lomond and in the Monte Cristo area. The increased load and stress from the storm moving in today, we could tip the scale and bring this old weak layer to life. As loading continues today I would avoid steep, upper elevation, north-facing terrain where the old snow from before Thanksgiving exists or stay on slopes below 30 degrees with no slopes above, below or connected that has a slope angle above 30 degrees.

  Click here for info about this layer and where it exists

  Below is a video from Doug Wewer on Ben Lomond Peak. We will be watching this layer near the ground to see snowfall from this storm adds enough stress to this layer to cause avalanches on it. It is not widespread but has been found in enough places that we can't discount it.

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2

  We have had multiple consecutive days of westerly winds averaging 10-20 mph and gusting above 30 mph at ridgelines. Ridgetops are already gusting above 40 mph this morning. With this storm, the westerly winds will continue and only increase. Expect gusts up to 50 mph at ridgelines today, and up to 60 mph at ridgelines tonight. As the storm continues to develop, the new snow may bond poorly to the old snow surface and we will expect to see wind drifted snow along upper elevation ridgelines and around terrain features, such as gullies and chutes, especially into the afternoon.

  Look for signs of wind-blown snow which often looks rounded and smooth, and sounds hollow. Other obvious signs include whumpfing, collapsing and shooting cracks. Also, look for slopes that were scoured or eroded and consider where that snow was transported.

  The simple strategy is to look for and avoid these slabs of freshly wind drifted snow on steep mid and upper elevation slopes.

• 

  Storm Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1

  The Ben Lomond area could be favored at the beginning of this storm cycle, today even a small avalanche can be dangerous as the conditions were previously shallow and you could be dragged through rocks, trees, and rugged terrain.

  When traveling today watch for increased snowfall, and see how this snow is bonding using small test slopes and quick snowpits. If snow totals end up being higher than predicted for the Ogden area mountains it should be possible to trigger soft slab avalanches of new snow.