Avalanche forecast

Hatcher Pass

Hatcher Pass Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
1 · Low
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Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The avalanche danger is CONSIDERABLE for WIND SLABS and PERSISTENT SLAB above 2500 ft.

Up to a foot of new snow and periods of extreme winds over the last week have created areas of dangerous avalanche conditions. 

Accidents tend to happen during or just after a storm. Patience and caution will be key when assessing terrain today. 

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SPECIAL ANNOUNCEMENTS: 

Areas throughout the state have received multiple feet of snow and many regions have considerable or high danger. Many areas do not have public avalanche forecasts. Check out avalanche.org to find your local avalanche center. Be sure to assess the snowpack before entering avalanche terrain. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Over the weekend extreme winds ravaged Hatcher Pass. Yesterday gusts on Hatch Peak topped out in the 80's with close to 30 hours of sustained strong to extreme speeds throughout the forecast area. Recent winds will have transported much of the available and new snow into stiff drifts and slabs on aspects leeward to the southeast. With winds this strong, expect to encounter cross-loading on more windward aspects as well. Strong winds this morning will continue to shift to the southwest before diminishing this evening. 

    Expect new wind slabs 6-12'' thick possible to human trigger on west through north facing slopes above 2500 ft generally 35° and steeper. There is a good chance that wind slabs triggered today could step down into old buried weak layers of the snowpack, increasing the size, complexity, and danger of this problem.

    Watch for stiff or hard drifts and use caution when approaching smooth rounded features.  Wind drifts may sound hollow or crack out from your ski tip as you travel across them.  Shooting cracks are signs of instability and indicators of this avalanche problem. 

    At mid and lower elevations where the wind had less of an effect, and if snow continues to accumulate, it will be possible to find softer storm slabs from all the recent snow. While more manageable, this problem is worth mentioning as snowpack structure in these locations is generally garbage. Use caution when navigating creek bottoms, gullies, or terrain traps even at low elevations. 

    Saturday's skier triggered wind-slab in April Bow. 

    Photo: Tim Rogers

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    While it's the new snow we're excited about, it's the weight of this new snow that is cause for concern in the snowpack. In the last week, Hatcher Pass has picked up close to an inch of Snow Water Equivalent. This newly added load to the snowpack is likely to be overloading and stressing buried weak layers and our generally poor snowpack structure. 

    Persistent Slab avalanches 1 to 3 feet deep will be possible to human trigger on southwest to northeast aspects above 2500' on slopes 30 degrees and steeper. 

    This problem could be triggered by a skier or wind slab avalanche stepping down into old buried weak layers. Today I'd expect to see some evidence of recent natural activity from this problem and would be very cautious when stepping out onto recently loaded slopes. Careful assessment and cautious route-finding will be required to navigate this problem. Freshly loaded slopes will be deemed suspect until proven otherwise. 

    Recent avalanches and collapsing are red flags and an indication of this problem. You can manage this problem by sticking to lower-angled slopes.

     

    A season's worth of poor structure is being tested by this recent storm. Forecasters and students have continued to find propagation in pits and recent activity confirms the likelihood of this problem.

Avalanche Discussion

RECENT AVALANCHES

Unsurprisingly, there were no observations from the field yesterday. 

On Saturday party and their dogs triggered and were caught and carried in a wind slab avalanche in April Bowl on the back side of Hatch Peak. This avalanche sympathetically triggered another above them. 

Since Monday, forecasters have observed natural wind and persistent slab activity on steep W and NW facing slopes above 3500'. 

See obs HERE. 

Regions covered