Avalanche Forecast
Regions: Olympics.
The avalanche danger Saturday will focus primarily on wet snow avalanches. Caution on steep solar aspects receiving direct sun during the warmest part of the day. Cornices may weaken Saturday. Avoid travel on or on slopes below overhanging cornices.
Detailed Forecast
Another mostly sunny day is expected Saturday with some high clouds at times. Warming should peak Saturday with freezing levels climbing to 8-9000 feet by Saturday afternoon. Winds should remain relatively light up to the Near Treeline Band and moderate Above Treeline.Â
Watch for loose wet snow conditions on steep solar slopes during sun breaks or thin high clouds, especially during the warmest part of the day, Saturday afternoon.Â
Older wind slabs have had the week to settle and strengthen and will no longer be listed as a specific avalanche problem. Any lingering older wind slabs should be confined to specific steep terrain features above treeline and will continue to stabilize Saturday. Continue to watch for recent wind effects below ridgelines and avoid steep slopes with obvious signs of recent wind loading.Â
Snowpack Discussion
Weather and Snowpack
An arctic air mass settled over the Northwest with fair, cold weather from the New Year through the second week of January. An atmospheric river moved over the Northwest about 1/17-1/18 with heavy rain seen up to at least 6000 feet in the Hurricane Ridge area. Three day precipitation totals through Thursday 1/19 were about 2.5 inches at Hurricane Ridge. An avalanche cycle likely occurred in the Olympics during this period.
The NPS rangers reported a storm total of 15 inches of snow at the Hurricane Ridge manual snow plot Thursday morning 1/19. Showers continued during the day Thursday 1/19, but our precipitation gage didn't record any precipitation after 9 am, possibly due to equipment problems. About a foot of snow fell at the Waterhole NRCS Snotel over a 24 hour period ending Friday morning 1/20.Â
Showers late Saturday and another band Sunday deposited about 4-6 inches of new snow as of Sunday afternoon at Hurricane, with strong S-SE winds.
Fair weather with light winds and cool temperatures have been seen Monday through Wednesday.
Light winds with warm air aloft allowed temperatures to climb above freezing midday Thursday and again Friday at Hurricane Ridge.
Recent Observations
NWAC pro-observer, Matt Schonwald, was at Hurricane Ridge Friday 1/20. Matt found 10 inches of settled recent storm snow generally well bonded to the underlying rain crust and not reactive. SE winds were forming shallow wind slabs on lee slopes near treeline. The recent rainfall had penetrated well into the snowpack. At a limited number of test sites, the 12/17 PWL was found to be rounding and unreactive in snowpit test and well over a meter down. We feel comfortable removing the persistent slab from the avalanche problem list moving forward.
A report from Klahane Ridge via the NWAC Observations page on Sunday indicated wind loading on the N slopes at 6000 feet. The rain had penetrated to about 3 feet in the snowpack and the 12/17 layer we have been tracking was well bonded and difficult to identify.
Avalanche Problems
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