Avalanche Forecast
Regions: Olympics.
Strong frontal systems will be moving across the Northwest this weekend and next week. Be prepared to change your plans especially if conditions are worse than expected.
Detailed Forecast
Strong alpine winds and moderate to heavy rain and snow will accompany a cold front across the Northwest Saturday afternoon to Sunday morning. This should bring a foot or more of new snow above treeline with a mix of rain and snow near treeline and rain below treeline. Temperatures may cool a little in the Olympics Sunday following the front.
New storm and wind slab near and above treeline should be the focus Sunday. Human triggered storm slab should be likely on varied aspects mainly above treeline Sunday while human triggered wind slab should be likely on lee north to east slopes.
A short minor break between weather systems should be seen Sunday afternoon. This may slightly decrease the avalanche danger.
The next strong system should begin to move into the Olympics and Cascades Sunday night. But be prepared to curtail your plans later Sunday if conditions deteriorate sooner than expected.
Early season hazards exist for much of the below treeline band throughout the Northwest, so ski and ride with caution.Â
Snowpack Discussion
Manual observations from Hurricane Ridge and automated observations from the Waterhole Snotel show around 15-20" of snow near 5000 feet as of Saturday. We have not received any snowpack observations from the Hurricane Ridge area for this season, but given the warmer temperature regime over the Olympics lately, we don't expect any persistent weak layer problems like those seen in the Cascades.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: Alpine, Treeline.
Likelihood: 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: North, North East, East, North West.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1