Avalanche Forecast
Jan 18th, 2019–Jan 19th, 2019
Alpine
4:
High
The avalanche danger rating in the alpine will be high
Treeline
3:
Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2:
Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3:
Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3:
Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2:
Moderate
The avalanche danger rating below treeline will be moderate
Regions: Cascades - West.
The Bottom Line: A strong storm will impact the West-Central zone Friday night and Saturday adding more snow/ rain to the area and keeping the avalanche danger elevated. Be patient Saturday. Stay off of open slopes greater than 35 degrees where you can trigger avalanches within the new snow.
Snow and Avalanche Discussion
Another round of heavy precipitation Friday night into Saturday will only serve to add more load to the snowpack and keep the avalanche hazard elevated. The avalanche danger will likely peak overnight Friday/Saturday as the heaviest and warmest precipitation impacts the area. However, heavy snow showers and moderate winds may cause very dangerous avalanche conditions to linger into the daylight hours. As the weather cools, and the snow showers decrease, avalanche danger will slowly decline, but if you find yourself in areas of sustained heavier snow showers, expect that the avalanche danger may locally maintain or increase.
We received reports of natural, human-triggered, and explosive triggered avalanches from the Mt Baker area Friday and given similar recent weather impacts, we suspect that the Mountain Loop may behave similarly. At least one of these avalanches released after several people traveled on the same slope. Avalanches occurred on W-N-NE aspects above 4800 ft, where mostly cold dry snow accumulated. A subtle weakness found between Thursday and Friday’s storm snow seemed to be the culprit in most of these events. We expect similar weaknesses within the storm snow again Saturday in the Mountain Loop.
Avalanche Problems
Loose Wet
Below the rain-snow line, you will find wet snow surfaces. This lower elevation snowpack is well situated to handle more water. That said, when we have wet snow on the surface, you may trigger loose avalanches on steeper slopes. These small avalanches can be a problem if they catch you off guard, or carry you into a terrain trap, such as gullies, creeks, and trees. As temperatures cool and the snow surface dries, these avalanches will become less and less likely.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood: Possible
Expected Size: 1 - 1
Storm Slabs
Fluctuating freezing levels and periods of heavy precipitation will create weak layers within the new storm snow. Storm slabs are more likely to fail naturally during periods of high precipitation rates and when the wind is actively blowing snow. As snow showers and winds decrease, storm slabs will slowly stabilize. This is a good time to be patient and allow these storm slabs to gain strength. Stay off of open slopes greater than 35 degrees where you can trigger avalanches within the new storm snow. If you travel to higher elevations, do not linger in locations where avalanches can run and stop. You can look for unstable storm snow as you travel. Small slope test, hand shears, and hand pits can help you identify weaknesses within the new snow.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 2 - 2