Avalanche Forecast
Regions: Olympics.
Rapidly changing weather and snow conditions are expected on Sunday. Back country travel is not recommended in avalanche terrain near and above treeline by Sunday afternoon.
Detailed Forecast
A deep low pressure system should move over about Cape Flattery and across south Vancouver Island Sunday morning and afternoon. This should bring stormy weather and heavy snow to the Olympics Sunday. This is a little faster than previously expected. A vigorous, strong front should rapidly cross the area and cause rapidly shifting winds Sunday.
The main avalanche problem Sunday should be increasing strong winds and increasing moderate to heavy snow rapidly transporting recent or new snow and building new wind slab on lee slopes. This is very likely to be northwest to southeast slopes. New storm slab should also be likely where there is rapidly accumulating new snowfall.
The pattern makes for a tricky forecast Sunday. Dangerous avalanche conditions are expected to develop Sunday afternoon. Back country travel is not recommended in the near and above treeline by Sunday afternoon.
Snowpack Discussion
Weather and Snowpack
The nonstop active weather pattern continues to push a storm system through the PNW almost every day or two with fluctuating but generally moderate snow levels.
The last storm impacted the area Wednesday through Thursday with a warming trend that peaked Wednesday night and very strong winds. About 10 inches of new snow was reported by the Hurricane ranger for the 4 days ending on Saturday morning.
A front on Saturday is causing west-southwest winds and there should be a couple inches of new snow at Hurricane by Sunday morning. Â
The mid and lower snow pack in the Olympics should generally be a stable mix of crusts and layers of moist and rounded snow crystals.
Recent Observations
NWAC pro-observer Matt Schondwald toured around the Hurricane Ridge area Friday. He found up to 20 cm of dense 1 F or P snow above the latest rain crust. Thin wind slab was generally not reactive except in isolated areas on N-NW lee aspects near treeline. Although cornices were large, they were generally firm and not sensitive. Matt observed evidence of a widespread natural cycle involving shallow slabs on northerly lee aspects that likely occurred Wednesday night during warming and a transition to rain. Windward slopes that had melted out a few weeks earlier had packed on a firm and in places icy thin cover. Overall Matt noted few current avalanche problems in the Hurricane Ridge area Friday.  Â
Hurricane Weather Station
Internet communications to the station have been disrupted at the NWAC office. We have identified the problem but unfortunately our hardware will not be repaired until early next week. We apologize for the outage and are working to get the station back up ASAP.Â
Avalanche Problems
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: Very Likely
Expected Size: 1 - 1
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: Likely
Expected Size: 1 - 1