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Observation: Meadows

Observation Date
2/11/2017
Observer Name
Greg Gagne
Region
Salt Lake » Big Cottonwood Canyon » Silver Fork » Meadows
Location Name or Route
Meadow Chutes
Weather
Sky
Overcast
Weather Comments
Windless. The overcast skies and filtered sun provided for some greenhousing by midday.
Snow Characteristics
New Snow Depth
12"
New Snow Density
High
Snow Surface Conditions
Powder
Damp
Snow Characteristics Comments

Quite dense storm snow. Greenhousing occurring by early afternoon with rollerballs and wet, gloppy snow at the surface on all aspects < 9000'.

Storm totals are about 30-40 cms (12-16"), with higher amounts at about 10000'. Quite a bit of settlement noted exiting in early afternoon.

Enough sun & greenhousing has dampened the snow surface on many aspects and they will be crusted on Sunday morning. Am guessing upper elevation north aspects will still hold soft, dry snow.

Comments

Nice to see a return to winter! Was finding a right-side up storm that was well-bonded to the old snow surface. I was not finding any instabilities in the storm snow, but did notice an Instagram post from @wasatchavyobs of a class 2 in Days Draw from a storm snow slab where they commented the new snow was very sensitive above 9000'. I suspect any sensitivities in storm snow will have settled out by Sunday morning.

Below about 9500' (which was at about the highest elevation of rain) the storm snow has insulated the wet snow and the old snow is wet/damp down at least 60 cms (2'). Even though we are expecting colder temperatures tonight (low to mid teens F) the storm snow will insulate the wet snow, so this will be slow to freeze. Sunday is looking warm, with warming temperatures throughout this week. Although we were getting quite bit of collapsing down in the damp snow, especially below 9000', the damp snow does not look especially weak, and appears to be tightening up somewhat. But it may still be possible to trigger loose, wet avalanches that gouge down to the damp snow in steep, low elevation exits (i.e. Maybird) on Sunday.

Where we were traveling today in the Meadow Chutes there were no signs of instability at all: the storm snow was not sensitive, it was well bonded to the old snow surface, and there was no wind loading. Above 9500' the hazard was Moderate, and close to Low. Below that elevation the hazard was Moderate where a loose, wet avalanche was possible on steeper aspects.

Looking ahead at mountain weather, am noticing a period of northeast and east winds. Something to pay attention to as this is typically uncommon for us, and leads to unusual drifting and loading patterns. Would be watchful for fresh wind drifts on Sunday morning at the upper elevations.

Video is of damp snow insulated by storm snow.

Video
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate