Avalanche Forecast
Regions: Olympics.
The avalanche danger should gradually diminish Sunday, however dangerous avalanche conditions persist, especially near and above treeline. Avoid steep slopes recently loaded with wind transported snow. Conservative decision-making remains essential.
Detailed Forecast
Light to moderate snow showers at cool temperatures are expected overnight and early Sunday before tapering through the day. Winds should be light, except light to moderate in the alpine.
Only light accumulations of new snow are expected and with cold temperatures and light winds this should not affect the current avalanche danger significantly. The avalanche danger should gradually decrease on Sunday. However, cold temperatures may help maintain older wind slab layers near and above treeline.
Careful snowpack evaluation and cautious routefinding will be essential at higher elevations Sunday.
Recent moderate to strong S-SWÂ winds will make wind slab most likely on northwest to southeast slopes, but keep an eye out on all aspects in areas of more complex terrain. Watch for firmer wind transported snow from Friday and possible deeper wind transported layers. Older wind slabs may be masked by shallow fresh snow.
Cornices won't be listed as an avalanche problem in this area, but avoid travel on ridges, where recent cornices may have formed and avoid slopes below cornices.
Snowpack Discussion
Weather and Snowpack
... Updated forecast to raise the danger level near and above treeeline in the Olympics due to the many recent triggered avalanches, Saturday March 4th.
The most recent wet warm storm arrived on Valentines Day 2/14 and formed the uppermost, very strong rain crust in the snowpack.Â
A series of disturbances in cool, NW flow aloft from Saturday 2/25 through Tuesday 2/28 deposited about 10 inches of snow at Hurricane. Very strong alpine winds were seen in most of the Olympics and Cascades on Tuesday.
Southwest flow aloft began to ramp up again on Thursday as the first in a new series of fronts crossed the Northwest. Strong southwest flow carried a second stronger front across the Northwest on Friday evening. At Hurricane, 24 hour new snow of 8 inches were received as of Saturday morning, with about 12-14 inches since Thursday. The latest storm snow was received with strong SSW alpine winds and moist, dense new snow above about 3-4000 ft and wet snow or rain below about 3-4000 ft.
Recent Observations
NWAC observer, Matt Schonwald was at Hurricane on Friday and found that ski tests were showing rapidly increasing propagation and increasing sensitivity of the deepening storm slab. Previous winds had loaded various slope aspects while south winds on Friday were loading N aspects.
...Updated  - From reports by NPS rangers early Sunday, there were at least three and possibly four separate triggered avalanches in the Hurricane Ridge area Saturday, March 4th. Including the areas known as Maggies, Hurricane Hill and Sunrise Face. This is indicating the recent storm snow remains sensitive to human trigger and more conservative decision-making remains essential until the storm and wind slabs settle further.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: Possible
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: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1