Cawley

Salt Lake » Little Cottonwood Canyon » Hogum » Hypodermic Needle

Hypodermic Needle

10,600'

Northeast

40°

Natural

Soft Slab

New Snow

New Snow/Old Snow Interface

20"

60'

1,500'

For the most part, new snow lies soft and unmolested from drainage bottoms to ridgelines. In Maybird, Hogum, and Coalpit Gulch, storm totals since wednesday seem to mirror ski resort study plot data from the upper cottonwoods, with up to a couple feet of light density snow sitting atop the nuclear MF crust from last weekend. Winds were calm from the NW all day, with sun shining through the low cloud deck occaisionally, but not enough to cause significant wet activity, at least in the higher elevations. SE-S-W will likely have a slight crust tomorrow. Only two significant avalanches were obvious today, in places where you'd expect to see some activity during a windy snowstorm. Most interesting was a long running, soft-slab avalanche originating in the alluvial feature beneath, and lookers right, of the choke of the upper chute in the Hypodermic Needle--just below where skiers commonly traverse out of the needle and onto the ridgeline between the Coalpit Headwall and the Needle. This avalanche failed on light density snow from wednesday, 3/20, which sits atop a pencil hard, brown MF crust, and just beneath a 2 inch deep, 1F slab of graupel from thursday morning, 3/21. Much of the crown was blown in, but a small portion was still exposed, and my best guess is that this slide ran during or just after the period of high precipitation intensity on 3/21. Debris ran to within a few hundred feet of the creek in Hogum fork, and was covered by new snow from the last few days, and I'd call it a D2.5--your Hummer would have been totaled, but it would still resemble a Hummer. Debris was still soft underneath ~10" of new snow, which corroborates my impression that the slide occurred early in this storm cycle. Another large slide occured in the eastern-most slide path on the coalpit headwall, with impressive deposition apparent ~1500' below the ridgeline. No other obvious slides in outer-LCC today, although it is a hoot to see the wet-slide carnage from last weekend just barely obscured by our new snow. Since thursday, 3/21, I've found the MF crust/stellars/graupel slab combination to continue to be sensitive, with quick snowpits, ski cuts, and cornice drops showing failure propagation in this layering is still possible. This is certainly a manageable problem, but I'm guessing this weakness will remain active for a few days on isolated terrain features where light density snow from 3/20 sits on top of a MF crust.