Aaron Rice

Salt Lake » Big Cottonwood Canyon » Days Fork » Days Draw

Days Draw

10,000'

Northeast

38°

Skier

Unintentionally Triggered

Soft Slab

New Snow

Graupel

16"

50'

500'

Party of 5. As we skied north down the ridge from the top of Days Draw we noticed much more active sluffing than we were expecting from our observations down lower while skinning up. One member of the party triggered a slab that propagated about 50' and was 6 to 18 inches deep indicating some wind effect though the snow density was mostly consistent and dry. Upon inspection it appeared that the new snow failed on about an inch of small graupel sitting on a pencil hard crust caused by the rain and warm temps before this storm. On our next run I triggered a very similar avalanche. This one was on a North facing slope and was significantly wider (200') as I intentionally cut the slope for a long distance. After I finished the cut the slope continued to propagate. This slope was smaller and the avalanche only traveled 150' downhill. Based on observations on the skin track and slope cuts on the descent the new snow is very sensitive only above 9,000'. I think this is because we have a rain/ melt freeze crust from last weeks warmth up to over 10k. Then last nights storm started as rain (or at least had very warm temps) below 9,000' that allowed for very good bonding to the old snow below that elevation. However, above the initial rain line the snow is still very sensitive sitting on a grauple layer that is sitting on a crust.