Register for an account and never miss a forecast again!
RegisterRegister for an account and never miss a forecast again!
RegisterDec 4th, 2017–Dec 5th, 2017
Snoqualmie Pass.
There is less confidence in the forecast above treeline, due to limited observations. Travel with more caution if venturing to higher terrain due to recent heavy storm cycle loading through Saturday where wind and storm slabs may need more time to heal.
Tree well hazard exists: Travel with a partner and keep them in sight and in communication in areas where there has been recent heavy snowfall.
Fair weather with gradual warming is expected Tuesday with gradually increasing easterly crest level winds.
This should allow for further settlement of the recent storm layers and cause an overall slowly decreasing danger.
Watch for areas of wind transport and fresh wind slab deposits if easterly winds increase above forecasted.
Small to large wind slabs should remain most likely on NW through E aspects on Tuesday and should become more stubborn or difficult to trigger. Watch for areas of firmer, wind-transported snow, mainly isolated to lee terrain features, such as just below ridges.
Loose dry avalanches are not listed as an avalanche problem type, but continue to watch for loose dry snow on steep terrain, where even a small avalanche of this type may be dangerous above terrain traps or where early season hazards exist.
Travel with a partner and keep them in sight and in communication in areas where there has been recent heavy snowfall due to tree well danger.
Remember that early season terrain hazards still exist, such as poorly covered rocks, vegetation and creeks, particularly at lower elevations.
Warm, wet weather before Thanksgiving caused wet snow and glide avalanches as well as significant snowpack consolidation. There are no known snowpack concerns below the Thanksgiving crust and in general, the snow received post-rain event has reportedly bonded well to that crust layer.
A series of frontal systems produced snow over the past week at all stations in the Cascades since the Thanksgiving warm period: Locations on the west side of the Cascade crest have received 1.5' to 4.5' with the most at Mt. Baker.
This includes the recent snow accumulation for the 48 hours ending Sunday morning along the Cascade west slopes, ranging from 5-27" with the most again at Mt. Baker.
The recent storm cycle ending early Sunday with 2-5 inches of snowpack settlement as of Monday afternoon.
Observations
North
On Saturday morning, the Mt. Baker Ski Area reported widespread 10-14" touchy, large ski-triggered storm slab on all aspects along with a couple similarly sized natural avalanches. During the day, the resort also reported 3 close calls due to tree-well incidents.
By Saturday afternoon, an NWAC pro observer found that slab layers were becoming more stubborn to trigger.
On Sunday, the Mt. Baker ski patrol reported many folks were skiing in the backcountry with no avalanches reported. Additionally, a private report to NWAC indicated small, thin wind slab high on north-facing slopes near the Mt. Baker ski area. Otherwise, no signs of instability. Plenty of point releases on S-facing slopes during sun breaks.
On Sunday, a Professional Guide was skiing in the Bagley Lakes area and despite many back-country skiers, saw only one small triggered shallow wind slab in a steep, loaded location. Layers from Friday were less reactive and healing
Central
On Saturday, the Alpental Ski Patrol reported generally well-bonded settled snow.
On Sunday, NWAC observer Jeremy Allyn was in the Alpental/Source Lake area. A lot of recent storm snow hasn't fully settled and there were still some storm layers giving moderate RP results in snow pit tests. Pockets of wind affected snow seen on high terrain. The low-density snow was deep and tree wells were a major hazard.
South
NWAC Pro Observer, Dallas Glass was out on Saturday in the Paradise area. On W-S-E aspects he found 8” new of new snow, well-bonded to 2 feet of previous snow on the Thanksgiving crust. He found 5400-6000’ W-SW-S-SE-E. He did not find evidence of storm or wind slab.
On Sunday, Crystal Mountain Ski Patrol reported 10” of new snow in the last 24 hours. The upper snowpack is generally right-side up and well-bonded to the Thanksgiving day crust. Winds on Saturday night also created a shallow surface layer of higher density snow giving minor cracking and likely small, shallow areas of wind slab.
Another Pro Observer was at Paradise on Sunday where the main story was the 9-10" of new snow that fell at slightly higher densities and precipitation rates, giving small storm slab on varied aspects. Several small loose-dry avalanches were observed in the near tree-line.