Ogden

Avalanche problems

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Likely

  Size

  3

  Drew said it well yesterday, “the difference between joy and terror is sometimes just a matter of a few degrees of separation – as in about 10 degrees of separation”. As we get farther from last week’s extreme danger ratings it will become increasingly tempting to step into steeper terrain, but with a persistent weak layer our options are simple:

  Low-Risk – High Reward

  High-Risk – High Reward

  We must continue sticking to low-risk terrain. With the tricky snowpack structure that we currently have, we may not be presented with obvious signs of instability such as cracking or collapsing. As well, tracks on a slope offer zero indication of stability – it could be the third, fifth, or first skier on the slope that triggers this weak layer.

  Patience is required, there is no outsmarting this problem. You are still likely to trigger a deadly avalanche 2-5’ deep in an area where the slab is thinner, such as rocky terrain, or in areas that have previously avalanched this winter. While it may be possible to find this layering anywhere in the Wasatch, I am most suspect of terrain along the periphery of the Cottonwoods such as Mill Creek, the PC ridgeline, Lambs/Mt Aire, Snake Creek, and the transitional zone toward the Bountiful/Sessions.

  What to do:

  • Dig down and if you see weak facets in the snowpack, avoid steep terrain
  • Choose a completely safe uptrack. You are often more vulnerable while ascending.
  • Expose only one person at a time and keep tabs on people all the time
  • Know what's above and connected to you - these avalanches can be triggered from a distance or below.
  • Ski cuts and cornice drops can be dangerous and dangerously misleading indicators of stability
• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2

  Lingering stubborn slabs of wind drifted snow can still be found in upper elevation terrain features today, particularly below ridgelines, subrides, and gullies. The elevated winds continue to increase the size of cornices on many ridgelines, making them more sensitive. Stay well back from - and avoid travel below - corniced ridges. A triggered wind slab or cornice may or may not step down into deeper weak layers. Look for signs of recent wind loading such as smooth, rounded, pillow-shaped deposits of snow and avoid those slopes.

  Photo of snow plumes coming off Ben Lomond yesterday - showing obvious signs of transport. (D.DeBruin)

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2

  As the clouds clear this morning, the strong sun and warm temperatures will cause the snow to get wet. While wet snow avalanches can be exceptionally challenging to forecast- particularly with variable cloud cover. This wet snow may produce small, loose wet avalanches. A few could be bigger if they entrain more snow as they roll downhill.

  Slopes with exposed cliffs and rock bands or gullies where the sunshine is concentrated will be the most likely places to see loose wet avalanches. The most dangerous locations will be in confined gullies this afternoon when these slides can happen on their own and hit you from above. Look for rollerballs and pinwheels rolling downhill and getting bigger as a sign that wet loose avalanches could start occurring.