Pre-Storm Conditions Rock Creek

SNOWPACK OBSERVATION
Submission Info
Forecaster
Wednesday, February 15, 2017 - 11:00am
Red Flags: 
37° 26' 42.3132" N, 118° 43' 31.3896" W
Snowpit Observations
More detailed information about the snowpack: 

Toured up from the East Fork parking past Rock Creek Winter Lodge, up moraines towards Tamarack Flat and up the north shoulder of Mt. Morgan South. Back down the same way. Beautiful day. Clear skies, light S and W winds with moderate gusts. Some blowing snow visible from the summits of Pointless Peak and Mt. Starr. Variety of snow surfaces to be covered by the next storm, ranging from surface facets to melt-freeze crusts to wind blown.

1020- Edge of the meadow behind Rock Creek Lodge, 9300'. Tair= 2deg. C, Tsurface= -6.5deg. C, Foot penn= 25cm, Surface grain forms: 1mm facets and 2mm surface hoar. Still cold in the morning at the bottom of the canyon.

1100- 9900' on an open flat spot at the top of the moraine. Tair= 7deg. C, Tsurface= -3.7deg. C, T-20= -3.6deg. C, Foot penn= 15cm, Surface grain forms: 1mm facets rounding in the intense sun. Surface slightly moist here. Top 15-25cm of the snowpack was F hard grains that faceted during the recent cold clear calm nights and is poorly bonded to last week's P+ hard rain crust which is below. Under the crust there are moist large rounded grains ranging from 4F to 1F.

Skinning up to the shoulder was challenging because of the poor bonding between the surface facets and the buried crust, you tended to slide down with each kick turn. Snow was surface facets (recycled powder, sugar snow, etc.) on shaded and N facing aspects. On solar aspects there was a variety of melt-freeze crusts on the surface ranging from P hard breakable a few cm thick to 1F hard thin "skin". Some E facing slopes had not yet developed a crust but the surface facets were becoming moist in the intense sunlight. Temps dropped quickly with a few thousand vertical of elevation gain.

1215- Opening on the top of the shoulder at 11100'. Tair= 3.5deg. C, Tsurface= -3deg. C, T-20= -8.5deg. C, Foot penn= 30cm, Surface grain forms: 0.5mm facets and wind broken fragments. Feb. 9th rain crust deeper here from previous wind loading.

Skiing on N aspects was excellent recycled powder. Thicker, moist snow down lower and last week's rain crust was closer under foot as we lost elevation. On the way down there was enough soft snow available for transport and enough light wind that our skin track had mostly filled back in. Wouldn't be surprised if fresh wind slabs were forming up high. Just goes to show that you don't need the big winds and big snow banners to tell you that slabs are forming. 15mph winds are enough to move loose snow and pack the grains tightly on leeward features.

Weather Observations
Blowing Snow: 
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