Bulletin d’avalanche

Hatcher Pass

Hatcher Pass Avalanche Center
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Danger d’avalanche

Sun
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 7 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

The danger is MODERATE above 2500' for Persistent Slab avalanches, and a skier or rider could trigger Wind Slab avalanches near or above 3500'. The danger is LOW below 2500'. You could trigger an avalanche where recent winds have built thick drifts of new snow near ridgelines, in alpine bowls, or along the sides of cross-loaded gullies. While less likely, it's not out of the realm of possibilities that you could trigger a thicker, more destructive slide on weak snow near the bottom of the snowpack. You're most likely to find trouble where the wind has stiffened the snow surface, or where the snowpack is generally shallow (less than about 2 feet). 

You can increase your chances of a successful day in the mountains by riding with a knowledgeable partner, carrying the appropriate rescue gear, and riding steep slopes one at a time. 

SPECIAL ANNOUNCEMENTS:

Come and celebrate with us at the 8th Annual HPAC Cabin Fever Reliever on Saturday, February 7th! More info and tickets here. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    As you climb in elevation or into wind-exposed terrain, avalanches will become easier to trigger. You are most likely to find trouble near ridgelines, alpine bowls, or along the sides of cross-loaded gullies. 

    Look for signs of wind transport such as freshly formed cornices, smooth pillows, lenses, or drifts of snow. Pole tests and hand pits are good tools to assess the upper snowpack, where you may find a stiff slab of snow over soft snow below. Shooting cracks are indicators that you have found sensitive wind slabs. 

    Shooting cracks were easy to make in areas where intense winds on Wednesday 14 blew snow from S/SW. 

    Photo: Hatcher Pass Avalanche Center

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Triggering a deeper avalanche up to 3' feet thick remains possible. You are most likely to trigger an avalanche where recent winds have stiffened the snow surface, or in shallow, rocky terrain. 

    • Avalanches will be more likely on slopes steeper than about 30 degrees. 
    • Small slides triggered in the new snow could step down into old buried weak layers, increasing avalanche size and consequence. 
    • Whumphing and collapsing of the snowpack are indications that there is weak snow failing near the ground. 
    • You may be able to trigger slides in gullies, alpine bowls, or on convex rolls where December's wind formed smooth, firm slabs over weak snow below.

    Large facets at the bottom of our snowpack.

    Photo: Hatcher Pass Avalanche Center

Avalanche Discussion

We aren't quite out of the woods yet, and it remains possible to trigger a large avalanche failing on buried weak layers near the ground. Snow coverage remains variable, with some slopes scoured down to the ground, while others have been loaded by recent snow and wind. You can hedge your bets by seeking non-wind-loaded terrain or terrain free of cliffs, exposed rocks, or gullies at the bottoms of slopes. Your odds of triggering a thick avalanche failing near the ground are low, but not zero. Before committing to steep slopes, take the time to dig down and assess these buried weak layers.  You are most likely to find trouble where the winds have stiffened the snow surface, built thick drifts, or where the snowpack is relatively shallow. You can increase your chances of a successful day in the mountains by riding with a knowledgeable partner, carrying the appropriate rescue gear, and riding steep slopes one at a time. 

Recent Avalanches:

Yesterday, we observed small natural wind slab/storm slab avalanches in steep terrain near the Punk Spines and on the west side of the Arkose Ridge. We also observed one larger natural persistent slab avalanche on the lower half of Divide Ridge near Idaho Peak (Observation).  It has been a week since the last human-triggered persistent slab avalanche. See Thursday 1/8 Microdot avalanche and Pro Observer observation here. 

Régions couvertes