Avalanche Forecast

Another mostly sunny day is expected Saturday with some high clouds at times. Warming should peak Saturday with freezing levels climbing to 7000 feet in the north and 9000 feet in the south by Saturday afternoon.

Winds should remain relatively light up to the Near Treeline Band and moderate Above Treeline. 

Watch for loose wet snow conditions on steep solar slopes as the temperatures climb under the direct or filtered sun, especially during the warmest part of the day, Saturday afternoon.  Moderate winds above treeline should help keep surface snow firmer,  limiting loose-wet activity on wind exposed slopes Saturday.

Older wind slabs have had the week to settle and strengthen and should now be confined to specific steep terrain features, mainly near ridges above treeline and will continue to stabilize Saturday. Continue to watch for recent wind effects below ridgelines and avoid steep slopes with obvious signs of recent wind loading. 

Weather and Snowpack

An arctic air mass settled over the Northwest with fair, very cold weather from New Year's through the second week of January. An atmospheric river moved over the Northwest 1/17-1/18 with highly variable weather seen throughout the Cascades during this event. Heavy rain was seen up to about 6000 feet or higher in the North Cascades and up to about 7000 feet or higher in the south with snow at higher elevations. Three day precipitation totals through Thursday 1/19 were roughly 8 inches at Mt Baker, 5 inches at Crystal and 1-2 inches at the Passes. Sleet and freezing rain Tuesday 1/17 at the Passes changed to snow at higher elevations at Stevens and Snoqualmie on Wednesday 1/18.  At Stevens and Snoqualmie Pass the freezing rain crust is about 1 inch (2-3 cm) thick.

The most recent storm cycle from last Thursday 1/19 through Sunday, 1/22, deposited 1-2 feet of snow along the west slopes of the Cascades with the greatest totals seen at Mt. Baker.

Strong S-SE winds Saturday night through Sunday morning built unstable wind slabs on lee slopes primarily in the central and south Washington Cascades.

Clouds and cool weather with little to no new snow accumulation occurred Tuesday and Wednesday.

A varied mix of sun, clouds or light snow showers were seen Thursday, with light winds.

Warming and sunshine Friday, near and above treeline, allowed temperatures to climb above freezing in most areas with some stations like Paradise reaching the 40's.   

Recent Observations

North

NWAC observer Lee Lazzara was in the Mt. Baker backcountry on Wednesday 1/25 and observed a generally stable snowpack for the terrain he traveled through. Winds slabs were present, but generally unreactive near and above treeline. Wind slabs were found on the more traditional NW-E-SE aspects. The most recent storm snow was well bonded to the 1/17 rain crust in the Mt. Baker area. Several glide cracks from the rain event are still visible and at least one natural glide avalanche occurred last weekend.

Lee was out in the Mt Baker area on Grouse Ridge Thursday 1/26. In this area, there were less recent wind effects with the last storm cycle and therefore, wind slabs were not encountered in terrain up to about 5800 ft. The rain crust from 1/17 was generally buried about 1 ft (30cm) and showed good bonding to the settled storm snow. No avalanches were seen or triggered, with nice settled powder conditions still providing good quality skiing. Lee noted widespread small surface hoar formed over the past few days and if buried by a light snowfall in showers may become a layer to watch out for with future loading.  Glide cracks were also seen on some slopes in this area below treeline.

Central

NWAC pro-observer Jeff Ward was on north slopes on Rock Mountain near Stevens Pass on Monday and found 50-65 cm of storm snow on the 1/17 crust with good stability and no recent avalanche activity.

A skier via the NWAC Observations page for the Source Lake-Bryant area on Monday reported 15-60 cm of storm snow on the 1/17 crust. Previous wind transport was evident at higher elevations. A skier triggered a large storm slab on a N-NE slope at about 4000 feet, which ran on the 1/17 crust. Natural and ski triggered, loose wet avalanches were also seen on solar slopes.

NWAC's Dennis D'Amico and Matt Schonwald were on Roaring Ridge in the Snoqualmie Pass area Tuesday 1/24. On N through E aspects at 4400 ft they found about 30 cm of right side up storm snow well bonded to the uneven and thick 1/17 freezing rain crust.

Dallas Glass was back in the Snoqualmie Zone Thursday 1/26, in the Denny Mountain area. Older wind slabs responsible for many triggered avalanches early this week, had now stabilized significantly and were no longer deemed an avalanche problem in this terrain. This observation is supported by the numerous aggressively skied terrain features throughout the Alpental Valley over the past few days with little to no avalanche activity. In snowpit tests, Dallas did find well formed facets above the 1/17 crust and this layer produced reactive snowpit tests, especially on solar aspects. These preliminary observations are limited in understanding the distribution or sensitivity of this layer, so more investigation is planned. 

South

The Crystal pro-patrol reported extremely sensitive new wind slabs on NW aspects Sunday morning. About 4-6 inches of new storm snow were transported by very strong S-SE winds overnight and early Sunday morning. This built very sensitive wind slabs on lee slopes by early Sunday. Wind slabs, mostly in the 6-8" range, released sympathetically and were running long distances. Shooting cracks were extending over 100 feet from skis.

By Monday and Tuesday the Crystal pro-patrol reported that previous reactive wind deposited snow had bonded and greatly stabilized with no new avalanches.