Hatcher Pass

Lawinenprobleme

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  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Hochgebirge
  • Waldgrenze
  • Unterhalb der Waldgrenze

  Wahrscheinlichkeit

  Likely

  Größe

  1–2

  Strong gusting extreme winds for 48 hours were recorded on 1/26 and 1/27 on Hatch Peak (Marmot weather station is currently down). Southeast winds blew steady at 25-35mph for more than 24 hours, with gusts up to 60mph at upper elevations. Even with the high-density snow from this wet storm, the sheer amount of new snow for transport makes it possible for these wind slabs to be large in size.

  It will be likely to find reactive wind slabs that are sensitive to human trigger on specific leeward aspects in terrain 30° and steeper. These avalanches could range in depth. It will be possible for larger wind slabs to "step down" to deeper weak layers in the snowpack, up to 5' deep. 

  If you travel today, look and feel for smooth, stiff, and hollow snow surfaces. Do pole tests and hand shears as you go to help determine slab continuity and behavior. Whumphing, collapsing, and shooting cracks are all red flags for this problem. 

  STORM SLAB AND DRY LOOSE

  With the colder temperatures, you are less likely to encounter storm slab avalanches as new snow is likely settling gradually and loosening. You may find lingering storm slabs at the lower-mid elevation where the snow was denser. Expect new snow to create dry loose instabilities at mid and upper elevations in steep and extreme terrain. 

  

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  Deep Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Hochgebirge
  • Waldgrenze
  • Unterhalb der Waldgrenze

  Wahrscheinlichkeit

  Possible

  Größe

  2–3

  At this time it is hard to determine the presence or reactivity of persistent weak layers buried deep within the snowpack. Due to the egregious weather and extended road closure, we (and you) have not been able to observe the snowpack at mid and upper elevations. We do know that due to the weight, quantity, and quality of new snow coupled with the depth of these old persistent weak layers, there is a lower likelihood of large natural avalanches. The snowpack structure is likely to have changed drastically over the last week, there's a good chance that much of the old faceted snow in our snowpack was either crushed or avalanched away. That being said, where this structure might have survived the storm, you could still trigger or remote trigger an avalanche in these now much deeper layers of the snowpack. This will be more likely on 30° or steeper slopes where old faceted grains are still intact. 

  Triggering this type of avalanche will be large and extremely consequential, certainly able to bury, injure, or kill a person and destroy a car or small. Expect deep persistent slabs to be upwards of 2 to 5' deep at this point with the potential to go to valley bottoms.