Galena Summit & Eastern Mtns

Avalanche problems

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Very Likely

  Size

  2–3

  Natural avalanches are likely, and human-triggered avalanches are very likely. Avalanches large enough to bury people and break trees could be much wider than expected and triggered remotely—from flat terrain below, above, and to the sides of steep slopes. Avalanche crowns could pull into relatively gentle terrain.  

  Snowfall and wind-transported snow formed slabs on many middle and upper elevation slopes and in isolated locations at lower elevations. Weak layers (facets, crusts and facets, and surface hoar) exist below the storm snow and below last week's storm snow. The slabs may not be particularly stiff but are proving very reactive, as evidenced by multiple natural and triggered avalanches observed as well as cracking and collapsing noted in most observations from yesterday.

  Conveniently, this new snow has come in extra cold, light, and fluffy, so sticking to mellow terrain that is not on, below, or connected to steep slopes today still offers high-quality sledding and skiing.

  

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Very Likely

  Size

  1.5–2.5

  Whether a weak layer exists or not, the combination of up to 20 inches of recent snowfall and moderate to strong winds makes natural and human-triggered avalanches very likely in windy, upper-elevation and alpine terrain. These slides may not be as wide or big as the Persistent Slab avalanches described above, but will still be large enough to bury people. Additionally, these slides can trigger or "step down" to Persistent Slab avalanches as they move downslope.

  Be on the lookout for wind-affected surfaces, feel for stiff hollow slabs overlying weaker or softer snow, and be aware of shooting cracks from your skis or machine as indicators to move to more sheltered terrain with softer snow. Steep, wind-loaded slopes should be off limits today, regardless of what elevation band you are in. Avoid playing in locations with overhead hazards—areas below steep, windy slopes that lack dense, live tree stands. 

  Winds are forecast to increase this afternoon, and the chances of triggering fresh wind slabs are expected to increase along with it.