Lawinenlagebericht

Hatcher Pass

Hatcher Pass Avalanche Center
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Lawinengefahr

Sat
Hochgebirge
2 · Mässig
Waldgrenze
1 · Gering
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 7 months ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

The avalanche danger is MODERATE above 3,500' for Persistent Slab and Wind Slab avalanches. The danger is LOW elsewhere. 

You may be able to trigger a wind slab avalanche where recent strong winds have built fresh reactive drifts, most likely along the sides of gullies or mid-slope convex rolls.

Triggering a larger slide failing near the ground is still possible. This problem is most concerning on steep, rocky slopes where the snowpack remains shallow. 

Look for and avoid slopes with signs of fresh wind loading, and be wary of entering steep terrain where you suspect a shallow snowpack or see exposed rocks in the steepest part of the slope. 

SPECIAL ANNOUNCEMENTS:

Come celebrate with us at the 8th Annual HPAC Cabin Fever Reliever on Saturday, February 7th! More info and tickets in the pinned post and on our website at hpavalanche.org.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Despite no recent snowfall and limited snow available for transport, recent strong winds have reset surfaces and blown any soft snow around, forming small wind slabs across the forecast area. You are most likely to find this problem mid-slope in cross-loaded gullies or convex roll-overs.  Winds may have scoured ridges, but you may still find isolated pockets of wind-drifted snow in more protected areas near ridgelines. 

    Look for a scalloped snow surface, freshly formed lenses or pillows of wind-drifted snow, or mid-slope drifts along the sides of cross-loaded gullies. Shooting cracks are a sign that you have found reactive drifts of snow. This problem is especially concerning where fresh slabs have formed in areas harboring a shallow snowpack, where even a small slide could step down, triggering a larger, wider avalanche on buried weak layers near the ground. 

    Elevated winds Wednesday through Friday likely created fresh drifts and small wind slabs in upper elevation terrain.

    Photo: Hatcher Pass Avalanche Center

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    On 1/31, a party on Microdot remote triggered a large persistent slab avalanche after several people had skied the slope (observation here). While no one was caught or injured, this occurrence confirms the reality of our current situation: it remains possible to trigger a consequential avalanche 1-3' deep on weak snow near the ground.

    You are most likely to encounter this problem in upper elevation terrain where our season's snowpack is resting on weak, sugary snow near the ground. Your chances of finding and triggering a persistent slab avalanche up to 3' deep will be highest near steep, shallow, rocky terrain.

    The easiest way to manage this problem is to select terrain with a steepness of less than about 30 degrees. If you do choose to get into avalanche terrain (slopes steeper than 30 degrees), you can pick terrain with a seemingly uniformly deep snow pack greater than about 3' deep—although be aware that you could trigger a slide from the edges or the middle of a slope where the snowpack is shallow and variable. 

    1/31 Microdot persistent slab avalanche. Photo: Hatcher Pass Avalanche Center

Avalanche Discussion

Weak snow near the ground and a recently skier-triggered slide on Microdot are reminders that triggering a slide failing near the ground is still possible. It can be tricky dealing with a stubborn, persistent slab problem because you will receive very little feedback from the snowpack, such as snowpack cracking or collapsing. 

Slopes with a shallow snowpack remain the primary concern, where buried weak layers are closer to the surface, making it easier for a skier or rider to trigger an avalanche. Be wary of stepping onto steep slopes with a shallow snowpack and exposed rocks—especially where the winds have stiffened the snow surface. You can hedge your bets by lowering your slope angle or seeking slopes that appear to be uniformly deep, have clean runouts, and have few exposed rocks in the upper part of the slope. You may be able to trigger slides from the edges or the bottom of slopes where the snowpack depth is shallow and variable.

RECENT AVALANCHES: 

Saturday, a party remotely triggered a large persistent slab avalanche on Microdot after several people had skied the slope. Read the forecaster observation for Microdot here. 

Earlier in the week, several natural avalanches were observed that occurred in the night or early that morning of the 27th/28th as wind speeds peaked. These include slides in Marmot Gullies, west-facing Marmot, Skyscraper, Eldorado, the north-facing aspect of 4068', Wimp Bowl, and the steep slopes at the back of Upper Willow Creek. See all recent observations here.

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