Avalanche Forecast

You can trigger Persistent Slabs on shaded slopes at mid to upper elevations. Persistent Slabs are difficult to manage and can break in surprising ways. To stay safe, avoid where the problem exists or if you go there stick to lower angle slopes and limit your exposure to large avalanche paths.

Warm temperatures and sun on Saturday will make it easier to trigger wet avalanches, especially in areas where they haven't recently run. Loose Wet avalanches may occur at higher elevations or on more shaded aspects (facing west, north, and east). While Loose Wet avalanches are often smaller and easier to predict, they can be dangerous in high consequence terrain. Avoid extreme terrain or areas where getting caught in a wet avalanche would be especially dangerous. This includes steep slopes above rocks and cliffs, tight gullies, or trees.

Minimal freeze Friday night raises concern for other warming and wet snow related avalanches. Watch out for snow-covered rock slabs at mid to lower elevations and slopes with exposed cracks where Glide avalanches could occur. Cornices have built in the past week. They typically fall during warming periods like what we will experience on Saturday. Whether you're walking on a ridge or traveling on slopes, give cornices plenty of room. Wet Slabs are very difficult to predict and can be very large and destructive. Avoid avalanche terrain, if you find slopes with unsupportive, wet snow or where a known weak layer is getting wet.

Temperatures have warmed over the last several days with mild daytime temperatures. Only shallow recent snowfall of 1-2 inches have accumulated, mostly Thursday with little to no snow earlier this week.  This has allowed for snowpack settlement and the development of a strengthening melt freeze crust. Older Wind Slabs have now stabilized. 

There has been recent slab avalanches, likely released over the past few days on a weak layer above a strong melt-freeze crust buried about 1.5 ft on lee slopes above Hurricane Ridge. This layer has been tracked over the past few weeks but has now produced at least two slab avalanches, each with crown depths about 1.5 ft and propagating over 100 ft wide on NE aspects between 5200-5400 ft. 

There are no other significant layers of concern in the snowpack at this time.

Observations

On Friday, NPS Rangers performed snowpack tests on a NNE aspect at 5,000ft. They reported test results indicating propagation on a layer of weak old snow about 2 feet below the surface.

On Thursday, 3/29 NWAC professional observer, Matt Schonwald saw evidence of two recent slab avalanches releasing on steep convexities on NE aspects between 5200-5400 ft. These avalanches released on a weak layer, poorly bonded to a hard crust. Several snowpack tests on this layer confirmed the propensity for avalanches to propagate.