Avalanche Forecast
Issued: Feb 7th, 2018 1:11PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet.
NWAC,
Northwest Avalanche Center
It will be possible to trigger a loose wet avalanche given continued springlike weather. Avoid steeper solar slopes if wet surface snow becomes deeper during the afternoon hours and don't expose yourself to cliffs or terrain traps such as gulleys.
Summary
Detailed Forecast
Very warm weather will continue along with strong winds and increasing clouds on Thursday.
A second night of above freezing temperatures will increase the threat of loose wet avalanches on Thursday morning, however increased cloud cover and winds attempt to limit the hazard. Expect the thick 10-12" crusts formed on Monday (1/5) to be partially thawed in some locations and that wet slush may be available to trigger a loose wet avalanche, particularly at lower elevations. Check the depth of your boot or ski penetration. At all elevations, avoid steeper solar slopes where wet, slushy snow becomes deeper than a few inches.
Snowpack Discussion
Cooling from Sunday afternoon through Monday refroze the top 10-12" of wet surface snow into a firm crust, however with temperatures staying above freezing for over 36 hours and temperatures climbing into the upper 40's to mid-50's at Mt. Hood Meadows stations, this crust should be thawing from the top down and loose wet activity was likely to have commenced by Wednesday afternoon.
The upper snowpack consists of a thick thawing crust at the surface, wet snow, old crusts, and well consolidated storm snow.
Observations
On Monday, Mt. Hood Meadows pro patrol reported that wind kept the snow firm except at the lowest elevations receiving solar heating. Runnels were in the terrain up to 7300'.
Mt. Hood Meadows pro patrol reported that Friday's widespread wet loose avalanche activity had become more stubborn and isolated near and below treeline by Saturday. The wet upper snowpack was still quite unconsolidated with the most recent 1/18 crust breaking down due to the sustained mild wet weather. Winds were strong near and above treeline but no snow was available for transport in area.
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: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 8th, 2018 1:11PM
