Archived

Avalanche Forecast

Jan 23rd, 2019–Jan 24th, 2019

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

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Cascades - East.

The Bottom Line: We've added a substantial amount of new snow to the snowpack of the East Cascades, and lots of avalanche activity has been observed. With the added load, large avalanches may be easier to trigger on multiple deeper weak layers. Avoid avalanche terrain if you see signs of instability such as shooting cracks, or hear whumphs. When the sun comes out, watch out for loose wet slides on steep sunny slopes.

Snow and Avalanche Discussion

The East Central Cascades picked up from 2.0" to .3" of snow water equivalent, depending on location. Snow accumulated rapidly as heavy snow fell and the temperatures warmed up, this caused a widespread natural avalanche cycle throughout the Cascades. Many large paths ran in the area, entraining wet snow as the debris ran through the water saturated lower elevation snowpack. Most of these appear to have ran within the storm snow, but some may have taken out persistent weak layers. It appears that it rained up to around 5,000ft, but uncertainty remains regarding how far down the water percolated into the snowpack.

Recent large slide off the north side of Wedge Mountain that entrained wet snow and broke some burned trees.

Avalanche Problems

Persistent Slabs

Put a large buffer of terrain between where you travel and any avalanche path. Slides may wrap around terrain features and surprise you and your group.

Large avalanches will be easier to trigger after yesterday's storm added to the slab over the weak layer. To the east the main concern lies in triggering the whole snowpack to the ground. Further west, the main layer of concern is surface hoar that was buried on the 17th. You can find this most readily on sheltered but open, shaded slopes, above the valley floor. Look for shooting cracks, recent avalanches, and listen closely for whumphs. Lack of evidence in one profile or snowpack test shouldn't be a reason to travel in more consequential terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 2 - 3

Storm Slabs

A substantial amount of new snow is to be found at elevations above 5,000ft, where precipitation fell as all snow. The snow fell cold initially, and temperatures warmed up as the snow accumulated. At upper elevations, the snow may be dry, and deep drifts are likely to be encountered. What is this new snow sitting on? Is there strong over weak? Is the new snow cracking, or do you see recent avalanches? Storm slab instabilities should decrease during the day as time helps settle these out. The deep new coat of snow will take time to bond, however. Travel with a conservative mindset, giving the snowpack another day to heal.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 2

Loose Wet

When the sun comes out, expect loose wet avalanches on steep, sunny slopes. These could entrain a large amount of heavy, wet snow if they make it down to lower elevations. If you see roller balls, recent loose avalanches, or notice you are sinking in past your ankle in wet snow, it's time to get off of steep slopes.

Aspects: South East, South, South West.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 2