menu
print

East Slopes North - Canadian Border to Lake Chelan

Issued: 6:59 PM PST Saturday, January 20, 2018
by Dallas Glass

NWAC avalanche forecasts apply to backcountry avalanche terrain in the Olympics, Washington Cascades and Mt Hood area. These forecasts do not apply to developed ski areas, avalanche terrain affecting highways and higher terrain on the volcanic peaks above the Cascade crest level. 

A stormy day on Sunday will cause the avalanche hazard to rise throughout the day. Watch for developing wind and storm slabs, and be prepared to select more conservative terrain as avalanche conditions deteriorate.

Danger Scalei
  • No Rating
  • Low
  • Moderate
  • Considerable
  • High
  • Extreme

Avalanche Problems for Sunday

Wind Slabi

Wind slabs can take up to a week to stabilize. They are confined to lee and cross-loaded terrain features and can be avoided by sticking to sheltered or wind scoured areas.

  • Avalanche Problemi
  • Aspect/Elevationi
  • Likelihoodi
  • Sizei

Storm Slabsi

Storm slabs usually stabilize within a few days, and release at or below the trigger point. They exist throughout the terrain, and can be avoided by waiting for the storm snow to stabilize.

  • Avalanche Problemi
  • Aspect/Elevationi
  • Likelihoodi
  • Sizei

Avalanche Summary:

An active storm cycle beginning Wednesday and extending into the weekend deposited 10-20 inches of new snow around the region. Observations indicate this new snow is bonding well to the 1/16 melt-freeze crust.

In exposed terrain winds have transported recent snow forming wind slabs on a variety of aspects.

Observations above treeline have been very limited leading to a high level of uncertainty in this terrain.

Buried surface hoar has been observed in the Cascade East - Central zone as of Wednesday 1/17. This layer has not been found recently in the north zone or in the area above Lake Wenatchee, however the layer cannot be ruled out entirely as its extent and distribution is still uncertain.

A supportive crust (1/5) formed from a widespread freezing rain event in the central-east zone, extending to the Stevens and Snoqualmie Pass areas. This layer was not present in the northeast from Washington Pass to Holden.

Snowdepth still decreases substantially east of the Cascade crest. In many areas below treeline, there has not been enough snow to present an avalanche danger.

Observations

North

On Thursday snow professionals in the Washington Pass area found good bonding of new snow to the old surfaces with favorable snow profiles and no avalanche activity, even traveling on steep slopes. No buried surface hoar was found in this zone.

Central

On Saturday an avalanche professional on Dirty Face Mountain near Lake Wenatchee observed a well bonded upper snowpack near and below treeline. No buried surface hoar was found and no avalanches were observed.

On Friday, NWAC observer Jeff Ward traveled near Mt Poe near Lake Wenatchee. No buried surface hoar was found over the Jan 16 crust layer in this terrain. Wind re-distribution was evident, especially in higher exposed terrain. Storm snow totals ranged from 16-20 inches in this area with no recent avalanches observed.

On Wednesday, 1/17, NWAC observers Jeremy Allyn and Jeff Ward traveled in the Icicle Creek drainage to 6800 ft. Buried surface hoar was found over a melt-freeze crust. The buried surface hoar was not limited to valley bottoms, but found to all elevations up to 6800 feet.

South

No recent observations

Forecast for Sunday:

Another round of precipitation and winds will arrive on the east slopes of the Cascades during the day on Sunday. The avalanche danger will increase throughout the day, peaking in the afternoon as precipitation and winds ramp up.

Moderate to strong winds will transport snow forming new and sensitive wind slabs. Watch for signs of winds actively transporting snow such as plumes, moderate wind speeds, and newly forming cornices. Identify and avoid avalanche terrain where the wind is depositing snow.

Shallow storms slabs will likely develop with precipitation during the day. As storm slabs grow, consider the consequences of the terrain where being caught in even a small avalanche may have more drastic consequences such as above cliffs, gullies, and open creeks.

Be prepared to select more conservative terrain as the storm intensifies and avalanche conditions deteriorate throughout the day.

No Corresponding Mountain Weather Forecast Available

USE AT YOUR OWN RISK

This Backcountry Avalanche Forecast is provided in conjunction with the US Forest Service, and is intended for personal and recreational purposes only. Safe backcountry travel requires preparation and planning, and this information may be used for planning purposes but does not provide all the information necessary for backcountry travel. Advanced avalanche education is strongly encouraged.

The user acknowledges that it is impossible to accurately predict natural events such as avalanches in every instance, and the accuracy or reliability of the data provided here is not guaranteed in any way. This forecast describes general avalanche conditions and local variations will always occur. This forecast expires 24 hours after the posted time unless noted otherwise.