Avalanche Forecast

Southwest flow should carry an energetic front and shortwave to the Northwest Saturday evening and night. Moderate west flow should carry a 2nd short wave, an upper low and a cool unstable air mass to the Northwest Sunday. This should cause southwest to west winds, rain or snow changing to snow showers and lowering snow levels on Sunday. Snow and snow showers should cause up to 6-12 inches of snow by the end of the daylight hours on Sunday with the most on the volcanoes and in the central Cascades in likely convergence. There is a chance of thunderstorms in the forecast along the west slopes Sunday afternoon and evening.

A mix of likely dangerous winter and spring avalanche conditions is likely along the west slopes on Sunday. The sun is getting much stronger and new snow may be very reactive to solar effects. The greatest danger should be in the afternoon to the end of the daylight hours.

New wind slab of a foot or more is likely on lee slopes mainly in the near and above treeline on Sunday. This is most likely on north to east slopes but possible on other aspects. Watch cracking and firmer or chalky wind transported snow. Snow pits may not be helpful due to variability in the snowpack.

New storm slab layers will be likely in areas where there is rapidly accumulating snow for more than a few hours. Warming daytime temperatures may contribute to upside down layers and instability. Pay special attention to slope convexities where storm slab is mostly likely to be triggered.

 Loose wet avalanches may be possible on steep solar slopes on Sunday. Don't overstay your welcome if you start seeing pinwheels or small initial natural loose wet avalanches. Be aware of terrain traps where even a small loose avalanche could have unintended consequences if you venture out on Sunday.

Cornices have grown large recently. Cornices can break much further back on ridges than expected and releases can be unpredictable during the spring.

Although not listed as an avalanche problem, large powerful glide avalanches can release unexpectedly so avoid areas below steep unsupported slopes or rock faces.

Weather and Snowpack

Snow accumulations Wednesday to Friday following the last front varied based on elevation, with only a few inches below 4000 feet and 6-21 inches above. The most snow was received at the NWAC Baker and  Paradise stations. The new snow since Monday is generally well-bonded to a moist crust buried March 22nd.  

Frequent March storms have built large cornices along ridges in many areas.

The mid and lower snowpack along the west slopes should generally be a stable mix of crusts and layers of moist and rounded snow crystals.

Recent Observations

Snoqualmie Pass avalanche professionals reported loose wet avalanches triggered by light rain running far on Wednesday in paths below treeline. Glide avalanches releasing to the ground off of rock surfaces were also reported near the same Snoqualmie Pass paths Thursday morning.

NWAC pro-observer Dallas Glass was in Kendall Peak area of Snoqualmie Pass Thursday and found small but sensitive wind slabs near treeline. Dallas also found loose snow concerns transitioning to shallow storm slab problem by mid-day with settlement and daytime warming.

The Mt. Baker pro-patrol reported only scattered and small soft storm slabs in area Thursday morning.  Stevens Pass pro-patrol reported strong west winds had redistributed the new snow, but that the new wind slab was stubborn and generally nonreactive to ski cuts. 

On Friday, Baker pro-patrol reported natural slab activity above treeline on Mt. Shuskan but only small loose wet releases in area and a generally right side up upper snowpack. A professional guide observation from the Snoqualmie Pass area Friday morning indicated generally well layered and bonded storm snow with increasing potential for loose wet avalanches by late morning.

NWAC pro-observer Lee Lazzara was out near Mt Baker on Friday and generally found 50 cm of storm snow on a rain crust from 3/21. He saw numerous loose wet avalanches on various aspects and despite warm temperatures some ski triggered loose dry avalanches were still seen on steep north slopes.

Further south Dallas Glass was out again near Paradise on Friday and found 60 cm of settled, bonded storm snow. He witnessed large rollerballs to 3 feet in diameter - watch out for those! Several small natural and ski triggered loose wet avalanches were seen on east to south facing slopes. There was significant wind redistribution of snow in the above and near treeline wind possible wind slab to 15 inches deep on north to southeast slopes.