Avalanche Forecast
Regions: Cascades - North West.
UPDATED 10:30 am Wednesday - Continued heavy precipitation at moderate temperatures is causing very dangerous avalanche conditions, extending to all elevations. Large natural avalanches are occurring Wednesday morning, running long distances to well below treeline. Travel in avalanche terrain is not recommended.
Tree-well and snow immersion hazards are very dangerous, so keep communication with your partner at all times.
Detailed Forecast
Periods of moderate to occasionally heavy rain and snow Wednesday at moderate temperatures will maintain large and unstable storm slabs and wind slabs below exposed ridges. Â
Storm slabs or winds slabs of 2 ft or more will continue to build Wednesday. Triggering a large avalanche is very likely in avalanche terrain Wednesday.
Large natural avalanches are likely on steep slopes Wednesday.
Travel in avalanche terrain is not recommended Wednesday and it will take time for the current dangerous conditions to stabilize.
Tree-well and snow immersion hazards are very dangerous, so keep communication with your partner at all times.
Snowpack Discussion
A very active weather pattern over the last week continues to target the Mt Baker area. A significant storm continues to build storm and wind slabs of 2+ ft in all avalanche terrain to well below treeline. Large natural avalanche activity was reported in the Mt. Baker vicinity on Tuesday with even more widespread avalanche activity reported Wednesday morning. Based on latest report, an avalanche warning has been issued for this zone Wednesday morning.
Below the recent storm snow, more than 5 feet of settling lower density snow sit above the most recent melt-freeze crust - it is deep out there!Â
Strong winds during Sunday's storm transported snow forming wind slabs on a variety of aspects creating very deep wind slabs particularly near and above treeline. Storm slabs were easy to trigger on Sunday and again on Monday and were running long distances.Â
Poor visibility and frequent storm conditions have limited observations above treeline during this period.Â
Observations:Â
...UPDATED WEDNESDAY MORNING... Mt Baker Pro Patrol reports very active avalanche cycle ongoing with large natural avalanches releasing from Shuksan Arm and all avalanche paths in area sensitive to ski trigger with slabs of 2 ft or more running long distances. Â
On Tuesday, NWAC Pro Observer Lee Lazara was in the Baker Lake area in below treeline terrain where he experienced significantly less snow accumulated above the recent crust (approximately 2') relative to Bagley Lakes. New storm instabilities had not yet developed in this location. There were various resistant planar interfaces within the storm snow from the past several days and the interface with the weak wet snow above a January 18th crust yielded hard test results.
On Tuesday, Mt. Baker Pro Patrol reported that a large avalanche was heard in the vicinity of Mt. Shuksan.
An avalanche professional in the Glacier Creek area reported little wind and occasionally heavy snow showers on Monday. A reactive storm layer within the most recent storm snow allowed storm slabs of 6-10" to be easily triggered on all aspects up to 5600'. A few natural storm slabs were observed as well.Â
On Monday morning, Mt. Baker pro-patrol reported control results producing widespread and easily-triggered 1'+ soft slab or loose dry avalanches that broke wide and ran far. Poor visibility prevented observations into the surrounding backcountry terrain.Â
Avalanche Problems
Storm Slabs
Release of a soft cohesive layer (a slab) of new snow that breaks within the storm snow or on the old snow surface. Storm-slab problems typically last between a few hours and few days. Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
You can reduce your risk from Storm Slabs by waiting a day or two after a storm before venturing into steep terrain. Storm slabs are most dangerous on slopes with terrain traps, such as timber, gullies, over cliffs, or terrain features that make it difficult for a rider to escape off the side.
Storm slabs usually stabilize within a few days, and release at or below the trigger point. They exist throughout the terrain, and can be avoided by waiting for the storm snow to stabilize.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 1
Wind Slabs
Release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Wind Slabs form in specific areas, and are confined to lee and cross-loaded terrain features. They can be avoided by sticking to sheltered or wind-scoured areas..
Wind Slab avalanche. Winds blew from left to right. The area above the ridge has been scoured, and the snow drifted into a wind slab on the slope below.
Wind slabs can take up to a week to stabilize. They are confined to lee and cross-loaded terrain features and can be avoided by sticking to sheltered or wind scoured areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 2