Avalanche Forecast
Dec 18th, 2018–Dec 20th, 2018
Alpine
Below Threshold
The avalanche danger rating in the alpine will be below threshold
Treeline
Below Threshold
The avalanche danger rating at treeline will be below threshold
Below Treeline
Below Threshold
The avalanche danger rating below treeline will be below threshold
Alpine
Below Threshold
The avalanche danger rating in the alpine will be below threshold
Treeline
Below Threshold
The avalanche danger rating at treeline will be below threshold
Below Treeline
Below Threshold
The avalanche danger rating below treeline will be below threshold
Regions: Olympics.
The bottom line: Significant snow and wind loading maintains dangerous avalanche conditions at higher elevations. At lower elevation, even a small avalanche could cause injury due to exposed rocks and vegetation.
Discussion
Hurricane ridge received 2.5" water equivalent of snow from Sunday through Tuesday at temperatures just below freezing. This snow was blown by strong winds on Tuesday night. Wind and storm slabs may exist in the terrain. You are most likely encounter avalanche problems above 4500' elevation where recent snow has fallen and enough coverage exists to submerge vegetation and rocks.
Prior to Sunday, much of the southerly terrain was void of snow cover. On shaded and wind loaded north through east aspects, snow depths averaged about 4 feet as of Sunday afternoon.
Prior to Sunday, much of the southerly terrain was void of snow cover. On shaded and wind loaded north through east aspects, snow depths averaged about 4 feet as of Sunday afternoon.
Forecast Schedule
For the 2018-19 winter season, avalanche hazard ratings will be issued for the Olympics Friday through Sunday and during holidays.
On days that the Hurricane Ridge road is closed, No Rating will be applied. We will continue to provide general snowpack and weather summaries for the Hurricane Ridge area even when No Rating is issued.
On days that the Hurricane Ridge road is closed, No Rating will be applied. We will continue to provide general snowpack and weather summaries for the Hurricane Ridge area even when No Rating is issued.
Regional Synopsis
Why has the avalanche danger been so high for so long? Two reasons: A very active and wet weather pattern and widespread persistent weak layer.
For perspective, the approximate snow totals from 12/9-12/18 are:
In many areas, a layer of buried surface hoar and/or weak sugary facets was buried on December 9th. This layer has been the cause in numerous natural, explosive, and skier triggered avalanches. As this layer gets deeper it gets harder to assess … in short, the scenario is tricky and getting more dangerous by the day.
Higher snow totals along the Hwy 542 corridor /Mt Baker area have driven several avalanche cycles during this period. Loading from recent storms has been more incremental to the east and south and we have not yet experienced a widespread cycle …
When will we reach the breaking point? It’s hard to say. What we do know is we have a deep weak layer, reports of very large explosives triggered slides at Mission Ridge and Crystal Mountain, and more storms on the way.
Be patient and continue to stick to lower angle slopes with nothing above you. This is a good time to avoid areas where avalanches can start, run, and stop.
For perspective, the approximate snow totals from 12/9-12/18 are:
- Mt Baker: 93â€
- Washington Pass: 45â€
- Stevens Pass: 66†mid-mountain
- Snoqualmie Pass: 59†mid-mountain
- Crystal Mountain 57†Green Valley
- Paradise: 70â€
- Mt Hood Meadows: 37†mid-mountain
- Olympics: 20â€
In many areas, a layer of buried surface hoar and/or weak sugary facets was buried on December 9th. This layer has been the cause in numerous natural, explosive, and skier triggered avalanches. As this layer gets deeper it gets harder to assess … in short, the scenario is tricky and getting more dangerous by the day.
Higher snow totals along the Hwy 542 corridor /Mt Baker area have driven several avalanche cycles during this period. Loading from recent storms has been more incremental to the east and south and we have not yet experienced a widespread cycle …
When will we reach the breaking point? It’s hard to say. What we do know is we have a deep weak layer, reports of very large explosives triggered slides at Mission Ridge and Crystal Mountain, and more storms on the way.
Be patient and continue to stick to lower angle slopes with nothing above you. This is a good time to avoid areas where avalanches can start, run, and stop.
Weather Synopsis
Active weather continues across the eastern North Pacific. The next Pacific storm to affect the region will approach the coast overnight. Warm frontal precipitation gradually increases overnight, especially in the Olympics and Mt Baker area.
A north to south oriented front will move into the Olympics and Mt Baker area overnight then shift across the WA Cascades Thursday afternoon. This will cause very strong southerly winds at crest level, bringing significantly rising freezing levels through midday Thursday with increasing precipitation.
Easterly surface winds through the passes may help limit rain but expect mixed precipitation forms through the day. Significant cooling arrives late Thursday afternoon behind the front with diminishing showers. An upper trough quickly moves east across the area Thursday night to maintain showers.
A rebuilding upper ridge of high pressure should allow for a break Friday.
A north to south oriented front will move into the Olympics and Mt Baker area overnight then shift across the WA Cascades Thursday afternoon. This will cause very strong southerly winds at crest level, bringing significantly rising freezing levels through midday Thursday with increasing precipitation.
Easterly surface winds through the passes may help limit rain but expect mixed precipitation forms through the day. Significant cooling arrives late Thursday afternoon behind the front with diminishing showers. An upper trough quickly moves east across the area Thursday night to maintain showers.
A rebuilding upper ridge of high pressure should allow for a break Friday.