Avalanche Forecast

Light winds and periods of light snow showers at higher elevations with continued cool temperatures should be seen on Sunday. A skiers delight! But continue to evaluate snow and terrain carefully on Sunday.

This weather should bring a gradually decreasing avalanche danger on Sunday. Storm layers that may exist above the new crust will slowly settle but could remain reactive to human triggers mainly in the above treeline Sunday. 

The greatest avalanche problem should be wind slab on lee slopes near and above treeline mainly NW-N-SE facing slopes below ridges. Watch for signs of firmer wind transported snow.

Watch for storm slab in areas that had rapidly accumulating snowfall.

Snow pits might be the only way to determine if persistent weak layers from earlier in January are still present in your area.

Weather and Snowpack

Two fair weather periods earlier this month allowed surface hoar and near surface faceting to occur. These persistent weak layers were buried intact on Jan 3rd and 11th and were reported throughout the Cascade east slopes.

A warm front about January 21st caused up to about a foot of snow in the northeast zone and lesser amounts in the central east and southeast zone with some mid and lower elevations changing to freezing rain or rain, creating a crust.

Another wet warm front was seen last Wednesday-Thursday with freezing levels climbing to near 7000 feet. Significant warm air associated with this system caused snow levels to likely fluctuate greatly before cooling arrived by Friday. 

This recent warm and wet weather should have cleaned out the January persistent weak layers in some areas, however, until confirmation, we will still list this as an unlikely problem along the east slopes.

A strong occluded front with strong winds crossed the Northwest on Friday. NWAC stations along the east slopes had about 4-14 inches of new snow by Saturday morning. Some areas are reporting a strong bond to the new crust and some a poor bond depending on when new snow arrived. However, even where good bonding exists there may be sensitive storm layers within the new snow. These storm layers may make for some sensitive triggered slabs and will take a bit of time to stabilize.

Recent Observations

NWAC pro-observer Tom Curtis was on Iron Mountain near Blewett Pass last Sunday and found the January 11th layer 35-70 cm down on NW-SE aspects in the below and near treeline bands. He found that the buried surface hoar crystals are rounding and the tests gave low quality results and did not indicate propagation.

Observers in the northeast zone on last Monday, looking for the January persistent  layers , indicated they may have been destroyed there by rain about January 21st.

Tom was out again on Table Mountain near Blewett Pass last Monday in the 4-6000 feet elevation range and found the January 3rd and 11th layers well defined down 70 and 50-60 cm and still giving sudden planar results with ECT test indicating propagation. He also noted crowns from natural avalanches that released on the January 11th layer late last week.

A report via the NWAC Observations page for Stemilt Basin last Monday near Mission Ridge strongly indicated that persistent weak layers at about 40 and 60 cm are still present east of the crest with test columns failing on isolation and evidence of previous widespread persistent slab avalanches.

Another report via the NWAC Observatons page for Friday for the Clara Lake area near Mission Ridge reported strong west winds transporting recent snow.

The North Cascades Guides reported 50 cm of storm snow over a rain crust near Washington Pass on Friday. The storm snow  lacked storm layers but test columns failed isolation at the crust.