Hatcher Pass

Problèmes avalancheux

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  1–1.5

  Moderate wind speeds overnight have likely built drifts 6-12" thick in isolated terrain that a skier or rider could trigger today. These small drifts are most likely confined to ridge lines and near the tops of peaks. Some slabs may overlie slick patches of old firm snow, making slides easier to trigger. While these will likely be small, they could knock you off your feet and carry you where you don't want to go. Expect slabs to be thicker and easier to trigger on the northern two-thirds of the compass (SW, W, NW, N, NE). 

  • Look for cracking in the newly drifted snow. 
  • Watch for a smoothed snow surface, dunes of freshly drifted snow, or fresh sensitive cornices forming along ridge lines; these are signs that a slope may be wind-loaded
  • These fresh slabs will likely be soft, but stiffer than fresh snow with no wind effect. 
  • Low visibility today may make identifying this problem difficult; be wary of upper elevation couloirs, alpine bowls, or slopes with any of the above signs. 

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Unlikely

  Taille

  1–2

  This season has been marked by strong winds, cold temperatures, and long stretches without snowfall. This has left the Hatcher Pass snowpack variable and weak. Today's snowfall is unlikely to push the snowpack to its breaking point, but it is time to start thinking about the impending persistent slab problem. Without a big load, triggering a large persistent slab avalanche is unlikely; however, in the off chance a skier or rider finds the sweet spot, these slides could have serious consequences.  If you were to find trouble, it would most likely be in areas that have remained relatively shallow this season, where strong winds at the end of December built dense slabs of wind-drifted snow up to 12" thick, over weak sugary snow below (Observation). These slides will likely be small in size, but large enough to knock you off your feet and carry you downhill. In these thinner areas, avalanches will likely fail near the ground on weak faceted snow. 

  In isolated places across the forecast area, older, thicker, and stiffer wind drifts formed by strong December winds still harbor ugly weak snow in the middle of the snowpack. These dense slabs of snow are helping armor the weak snow below, making avalanches difficult to trigger. In these deeper areas, avalanches will likely fail on weak snow near the middle of the snowpack on weak sugary snow, but may step down to basal weak layers. Many S and SE-facing slopes still lack enough snow to connect entire slopes to produce large avalanches. While it's unlikely this problem exists on many slopes, there may be other slopes harboring pockets of old snow. Be wary of slopes with more than just recent snowfall.