Valanga

Rock Creek - It Never Quite Got There

Clancy NelsonEastside Region
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Quick report

I went to Rock Creek to see who was winning the ultimate battle between cold temperatures, clouds, and springtime sunshine. There were some small signs of wet loose instability and surface warming, but ultimately, it never quite got there.

Small natural and triggered rollers up to 11,500 ft., mostly on east and south aspects. Some on northeast.

Weather

Air Temp
20s to 30s
Cloud Cover
scattered
Wind Loading
none
Recent Snowfall
T to 25
Snow Avail For Transport
moderate amounts

Cold morning temperatures and clouds delayed snow surface thawing today. By late morning, cloud cover was retreating toward the Crest. I did see a few stray snowflakes fall. By 2 pm, skies were mostly clear. Light north winds were cold and increased slightly in the afternoon. There was no blowing snow anywhere. Temperatures stayed below freezing except at lower elevations in the afternoon.

Snowpack

Basically, all recent storm snow is sitting on a melt-freeze crust. There's less recent snow in this drainage than from Mammoth, north. The underlying crust is thinnest on steep, true north-facing slopes near and above treeline. North-facing terrain near and above treeline never thawed and held soft, dry snow.

  • Below 9500': Dust on crust. Localized areas up to 10 cm F hard precip particles on the crust where drifted in. That's what was thawing 1st.
  • 9500'-10500': 15-20 cm F PP on mostly supportable crust. In some openings, there is a 4F breakable crust on the surface with 15-20 dry snow underneath. On northerly aspects in this elevation band: 2nd, harder crust down 30 cm with facets underneath. 3rd, then a thick, hard crust down 45 cm below the surface.
  • >10500': mostly wind-scoured. Sheltered areas had 5 cm transitioning from dry to moist on the surface over a crust.

Isolated/localized cracking at a kick turn in older wind-drifted soft slabs.

Avalanche

I intentionally triggered 2 D1 wet loose avalanches on east-facing slopes: one at 9200' at 10:30 am and one at 10900' at 1:15 pm. Both were triggered in areas with either shallow snowpack or near rocks.