Steamboat & Flat Tops

Avalanche

Max Strotbeck · Feb 15, 2024 · Steamboat & Flat Tops

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Observation photo 1Observation photo 2Observation photo 3Observation photo 4Observation photo 5

Weather

Skies were overcast and snow was falling steady around 2cm an hour. Winds were moderate with strong gusts from the southwest. Temperatures were in the mid-to-upper twenties.

Snowpack

Height of snow ranged from about 100-150cm, apart from the southwest (windward) side of the Little Japan ridge, which was scoured and very thin, composed of faceted snow beneath a wind and melt-freeze crust. About 15cm of new snow that began falling yesterday evening sat atop a 2-3cm crust on southerly aspects and decomposing fragments on northerly aspects. I found a layer of concern in the mid-pack on a northeast slope (small surface hoar crystals on which propagation occurred on hard taps in an extended column test) and a crust buried 40cm deep on south and southeast slopes, though I did not conduct instability tests on this crust. As I walked on the ridge, newly formed shallow wind slabs broke off remotely, and I easily triggered shooting cracks on this wind affected snow.

Avalanche

I intentionally triggered an avalanche on an east aspect below treeline while stepping just off to the leeside of the ridge. It was about 45cm deep and broke on a 3cm crust. It's quite possible this slope had avalanched mid-January (I had taken a roadside photo of a natural avalanche that occurred off the east aspect of this same ridge) but hard to tell given the poor visibility today. SS-ASc-R2-D2-O