Avalanche Forecast
Regions: Olympics.
Conservative decision making will be essential Tuesday as recent storm and wind slabs will require additional time to settle and stabilize. Avoid steep open slopes showing signs of recent wind transport. Best to confine travel to lower angled terrain away from wind effects.
Detailed Forecast
Additional showers are expected Tuesday at continued cool temperatures. Showers should generally be fewer and taper by late Tuesday.Â
Moderate west winds at ridge level should persist Tuesday before diminishing late Tuesday.Â
Recent or new wind and storm slabs will be the main avalanche problems in the Hurricane Ridge area and vicinity.
New wind slab is mostly likely to be found on NW-SE facing slopes. Firmer wind transported snow and snowpack cracking can be good signs of wind slab or storm slab instabilities.
New storm slab is likely in areas where new snow rapidly accumulates for more than several hours.
Cloudy cool conditions Tuesday may limit the development of loose wet snow but the sun is gaining power so watch for the development of loose wet snow on solar slopes if extended sun breaks occur.Â
The avalanche danger should gradually decrease Tuesday with less wind and slow settlement and stabilization of new snow and fairly cool temperatures.Â
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Snowpack Discussion
Weather and Snowpack
Storms have moved across the Northwest at a nearly daily frequency the past few weeks with fluctuating but generally moderate snow levels.
Storms last week arrived with a warming trend and very strong west winds. Â Settled storm snow of 10 inches was reported by the park ranger at Hurricane for the 4 days ending on Saturday morning.
A front on Saturday deposited another 5 inches of snow with W-SW winds at Hurricane ending Sunday morning.
A deep surface low-pressure system moved across the Olympic Peninsula Sunday causing very stormy weather.Â
Cool showery weather Monday continues to deposit additional snow at lower temperatures.
New storm amounts in the Hurricane Ridge area are about 10-15 inches over the past 36 hours.
Strong winds and recent storms have created widespread wind and storm slab problems, creating dangerous avalanche conditions.
The mid and lower snowpack 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 Schonwald 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 and anticipate the station to return online sometime Tuesday, March 15th.  We apologize for the outage and thank you for your patience. It should be back up tomorrow!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: 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
Loose Wet
Release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. They generally move slowly, but can contain enough mass to cause significant damage to trees, cars or buildings. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
Travel when the snow surface is colder and stronger. Plan your trips to avoid crossing on or under very steep slopes in the afternoon. Move to colder, shadier slopes once the snow surface turns slushly. Avoid steep, sunlit slopes above terrain traps, cliffs areas and long sustained steep pitches.
Several loose wet avalanches, and lots of pinwheels and roller balls.
Loose wet avalanches occur where water is running through the snowpack, and release at or below the trigger point. Avoid terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.
Aspects: South East, South, South West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 1