Avalanche Forecast

While there are no official avalanche problems in the forecast, there are a few potential hazards you could encounter in the backcountry right now. Most prominent are the variable surface conditions that could pose a challenge for some travelers. As the snowpack continues to transition, keep typical spring considerations in mind like wet snow avalanches, glide avalanches, and cornice falls. Be on the lookout for opening creeks. Avoid large consequential slopes where you find wet unconsolidated snow surfaces.  

The storm on Monday and Tuesday brought 10in of snow to the Baker area above 4000ft. The recent snow settled quickly throughout the week with periods of sunny skies and warm temperatures. A wet loose avalanche cycle ran its course on Wednesday and Thursday. The potential for lingering wet loose instabilities may still exist in very steep sun exposed terrain as it warms up throughout the day on Friday. A surface crust can be found on most slopes maintaining good snowpack stability but creating challenging skiing and riding conditions. If you venture into high elevation north facing terrain, you may still find dry snow and small wind slabs in isolated areas. Steer around slopes steeper than 35 degrees if you see evidence of recent wind drifted snow. Remember that even a small avalanche can have severe consequences around terrain traps like gullies or cliff bands.

March 27th, 2019

Enter Spring

If you’ve been in the snow recently, the wintery conditions of early March may seem worlds away. You may be in for a surprise if it’s been a while since you were in the mountains. The weather has taken a turn towards spring in the last couple weeks and the Cascade snowpack the has undergone major changes. Unseasonably warm temperatures and strong sun followed a month-and-a-half of cold, winter storms. Mid-elevation weather stations stayed above freezing from March 15th-22nd with high temperatures reaching the upper 50’s to low 60’s. For an in-depth survey of the regional snowpack, we’ll divide the terrain up by aspect and elevation.

A graph showing temperatures between 4,000-5,000ft around the Cascades from the 16th-21st.

Aspects

Northerlies

Along with the warm temperatures, the spring sun has played a major role in warming snow surfaces. The result is a snowpack that varies by aspect. In most regions, shaded and northerly slopes remain relatively unchanged. Aside from some settlement and firmer or moist surfaces, the snow on north aspects is almost entirely dry. Even some low elevation north slopes are still holding snow.

Sunny slopes

The snowpack on east through south through west aspects is a different story. The strong March sun melted snow surfaces and drove melt-water into the snowpack. This is most dramatic on steep (over 35 degrees) southeast through southwest slopes below 5,000ft.  In some areas, you can find meltwater up to 3 feet below the snow surface with drainage channels well established. Between this warm period and rain events in the first half of the winter, the entire snowpack has transformed to melt forms. Of note is that as of the 27th, these solar aspects have only undergone partial freezes with lower layers remaining unfrozen. Cooler weather may continue to strengthen these slopes.

A glide avalanche (D2) released from a rock slab late on the 20th. Lichtenberg Mtn, 5,100ft, SE aspect. Other glide avalanches occurred on the 20th at Snoqualmie Pass and in Tumwater Canyon. Photo: Josh Hirshberg

Elevation

Low elevations

As you travel from low valleys to higher peaks, you’ll notice a major difference in the snowpack based on elevation. With all the low-elevation snow this winter, there are still some cold, shaded slopes holding pockets of snow down to 1,000ft, especially east of the Cascade Crest. However, most slopes below 3,000ft have lost much of their snow cover. Many low elevation, sun-exposed slopes are bare, especially in areas that previously held less than 3 feet of snow. The low elevation snowpack is no longer substantial enough to allow for easy travel over snow or widespread avalanches.

Loose wet avalanches on the south side of Table Mtn, near Mt Baker. 3/17. Photo: Pete Durr

Mid-elevations

At mid-elevations, around 3,000-5,000ft, the snowpack is still deep and layered. Many slopes at this elevation band near and west of the Cascade Crest are holding 6-10 feet of snow. This is also where you’ll find the most dramatic variation in the snowpack based on aspect.

High-elevations

Above 5,000ft you’ll encounter a snowpack similar to what you may have found around the 1st of March. Upper elevations have stayed mostly dry. The most sun-exposed slopes have surface crusts but have not seen much water or change to melt forms below the surface.