Lawinenlagebericht

Hatcher Pass

Hatcher Pass Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 8 months ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

The storm has cleared, and frigid temps are in place for the day. Two feet of light snow has fallen with minimal wind effect. The snow is settling, but avalanches are still likely. Today, the avalanche hazard will increase as you climb in elevation. 

Above 3500', the avalanche danger is CONSIDERABLE where STORM SLABS could fail 2 ft deep. At mid elevations, the danger is MODERATE, where new snow has seen less wind effect but could still produce avalanches on specific terrain. Below 2500' the danger is LOW. 

You are most likely to trigger an avalanche at upper elevations, where light winds thickened the low-density snow into a cohesive slab. At mid and upper elevations, there is a possibility of triggering a PERSISTENT SLAB avalanche on old faceted snow near the ground.

Low danger doesn't mean no danger; sloughs and small avalanches could still be possible in steep gullies at low elevations.

Remember, most avalanches happen during or within 48 hrs of a storm. Give this recent snow some time to adjust before testing its strength.

SPECIAL ANNOUNCEMENTS:

Join us for our next State of the Snowpack chat on Wednesday, January 14th, at the Blue and Gold Boardshop in Wasilla with guest speaker Adam Sullivan, the mountain manager from Skeetawk.

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

Lawinenprobleme

  • Storm Slabs

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

    Over a 48hr period between January 5th and 6th, Hatcher Pass received over two feet of snow, effectively doubling our snowpack. This snow was exceptionally low-density and only lightly wind-affected. Lower elevations received less snow, but still well over a foot, with Frostbite registering about 16'' and just over an inch of water. 

    What this means is that as you travel throughout the forecast area, you can expect the new snow to range in depth and density, both as you climb in elevation and as you travel from sheltered to wind-affected terrain. Where new snow was protected, it may be loose and easily sluff. In exposed areas, light southwesterly winds will have thickened and increased the snow's density into a more cohesive slab, and may even have a thin wind crust on top. 

    • As you climb in elevation, storm slabs will become deeper, stiffer, and easier to trigger. Storm slabs up to 2' deep are possible at upper elevations.
    • Avalanches will be most likely on slopes steeper than 35° 
    • Watch for cracking or collapsing within the new snow; this is evidence that you have found a consolidated slab of new snow capable of making avalanches. 

    At low elevations or in sheltered terrain, triggering a slab avalanche is less likely, but in steep terrain, you could trigger loose snow avalanches or sluffs that could knock you down and rake you through the rocks and alders.

    Photo: Hatcher Pass Avalanche Center

    Evidence of recent and mid-storm slab avalanches running naturally on Marmot.

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1.5–2.5

    For over two months, our thin snowpack sat stagnant, faceting and rotting under cold, clear skies. Periods of extreme winds scoured this thin snowpack and created dense, isolated slabs. Now, all this new snow has fallen on this old, rotten snow and scattered slabs, creating the potential for avalanches to fail at or near the ground.

    • It will be possible to trigger a persistent slab avalanche 2-3.5' deep at mid and upper elevations, where old weak snow is preserved on the ground.
    • Persistent slabs will be possible where faceted snow is protected by stiff slabs in gullies and shallow depressions, and also where new snow fell on loose facets on the ground. 
    • Unlike the new snow, an avalanche on these layers would likely be unmanageable.

    With a limited amount of observations, uncertainty remains about how this old, weak snow will hold up to its new load. Whumphing and collapsing of the snowpack are indications that there is weak snow failing near the ground. Hand pits will easily reveal if you're traveling over old weak snow or firm slabs.

    Good travel protocol can help limit the consequences of an avalanche. Travel one at a time, choose safe points to stop, and keep eyes on your partners.

    Avalanches could fail on old faceted snow near the ground.

    Photo: Hatcher Pass Avalanche Center

Avalanche Discussion

Hatcher Pass received upwards of two feet of low-density, cold snow at around 1.5" of Snow Water Equivalent over a 48-hour period earlier this week--a welcome relief to a month-long drought with extreme winds. This new snow fell on a variety of surfaces, including dry ground and rocks, loose facets, breakable crusts, and firm wind slabs. 

Overall structure in the snowpack is poor, with new snow overlying old, weak, faceted snow and isolated slabs throughout the forecast area. Uncertainty exists about how the snowpack will adjust to its new load, but it's likely that Hatcher Pass will have a lingering, persistent slab problem that will be slow to resolve. 

Ski with a partner, practice with your rescue gear, and use safe travel protocols like skiing one at a time and stopping at points of safety. 

Early-season obstacles such as willows, rocks, and ice still exist below this new, light snow. Travel is difficult, and trail breaking is arduous. With frigid temps to close out the week, cold injuries are a serious threat. Cover exposed skin, and check your partners for signs of frostbite. 

Recent Avalanches:

Yesterday, with good visibility, forecasters in the field observed several soft slabs that failed naturally during or late in the storm. Avalanches were observed on the west and east aspects of Marmot, and the northerly aspects of Powder Pimple and Hatch, and southerly aspects of Skyscraper. These avalanches were relatively small, D1 -D1.5, failing on or near the ground, and running only a few hundred feet. See all recent observations here.

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