Hatcher Pass

Small human triggered wind slabs were observed on Eldorado Bowl on Jan 12th.

Numerous large natural avalanches and one remotely triggered avalanche (picture below) were observed after a strong wind event on 1/14.

1/14/22 – Peak x4068, NE, 3500′ – Red “X” marks trigger point for large remotely triggered avalanches.

1/14/22 – Remotely triggered avalanche on x4068. See overview picture under Persistent Slab Problem details.

1/14/22 – Frostbite Area, NNE, 3600′, Large natural slab avalanche. A good picture showing scoured ridgelines and wind-loaded gully sidewalls and terrain features.

1/14/22 – Skyscraper, E, 3500-4000′, Natural Slab Avalanche

Each time the snowpack is loaded, the avalanche hazard rises and natural avalanches occur. Yesterday was one of those times. Thursday and Friday’s (1/13-14) strong winds drifted January 11th’s 3-4″ of new snow overloading weak layers resulting in natural avalanches. Winds died down last night and are expected to remain light today through tomorrow. This will allow the snowpack to slowly improve in stability over time, as long as it is not loaded again. The NWS forecast is calling for 5-7″ of new snow which should begin late in the day, if we see larger amounts of new snow in this storm, the avalanche hazard may increase for Sunday.

Today these problems will continue to linger. We are dealing with a tricky and untrustworthy snowpack. Avalanche behavior will be difficult to predict. Human triggering and remotely triggering large avalanches 1-3.5 feet deep will be possible. The average depth for persistent slab avalanches is expected to be 1-2 feet deep.

Yesterday we identified at least 5 new significant natural avalanches which occurred during 1/13-14 strong winds. It is likely that other natural avalanches occurred that we did not observe due to poor visibility. We remotely and sympathetically triggered a series of large avalanches near ridgeline 900 feet wide, 1 to 3.5 feet deep from a low angle adjacent slope (see picture under Recent Avalanches). While there will be some improvement in conditions from yesterday to today, the problems are lingering.

The flaws in the snowpack are widespread, but the problem locations are specific. The flaws are buried combinations of crusts and facets (sugar snow). The locations include recently wind loaded areas, on NW, N, and NE aspects at mid to upper elevations.

While we are pointing out the most likely locations for triggering avalanches today, the distribution of this problem is more complex. Other locations for this problem exist, but are less likely to human trigger. These locations include previously wind loaded slopes from the Bora (Jan. 2-3) wind event on SE through SW aspects at mid to upper elevations. Please review this previous forecast for more details for lingering problems in these locations.

Safer locations lacking this avalanche problem are lower angle slopes 25º or less and out of the runnout of steeper slopes from above.  It’s fairly easy to identify slopes lacking problematic wind-loaded snow. These areas are scoured down to the December 26 rain crust and are shiny and crusty on the surface.

If you head into avalanche terrain today, utilize strict safety travel protocols, travel one at a time from safe zone to safe zone, only have one person on slope at a time, ensure all members of your party are carrying and know how to use beacons, shovels and probes, and avoid slopes with terrain traps.

1/13-14/2022 – Marmot Weather Station (4500′) – Strong SE winds drifted and transported snow on NW, N, and NE aspects on Friday. It will be important to note that 1/13-14 winds built new slabs up to 7-10” thick, however, these sit on deeply buried weak layers which could fail up to 3.5 feet deep.