NWAC has the preliminary report [pdf] for the Stevens Pass – Tunnel Creek avalanche that killed 3.
Here’s the high level overview:
Slope specifics: starting zone elevation 5800 ft, SSW exposure, 42 degree slope
Fracture line details: SS-AS-O-R2-D3; Slab size and structure—32 inch deep x 200 ft. wide soft slab (Fist to 4F hardness) released to surface hoar layer above early February crust (Pencil hardness)
Avalanche details: Slide caught 5, one of whom was able to arrest by holding onto tree; remaining 4 caught were carried about 2650 vertical feet through a twisting, tree ringed chute
Fatalities / Injuries: Three skier fatalities, one skier caught, deployed air bag, partially buried, uninjured, and extricated with the help of rescuers