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Easter egg hunting
Location Name:
Forecaster Observation - Eastern Mission Range
Observation date:
Sunday, April 12, 2020 - 18:15
Is this an Avalanche Observation:
Yes
Observation made by:
Forecaster
Tabs
Quick Observation
Chased larger storm totals in the Mission Range, accessed from the east side.
8" to 12" of new, "right-side-up" snow, settled through the day with sunshine and warming temperatures.
Minimal signs of wind transport until we reached 8,000', at which point we noted a natural D1.5 wind slab and some light drifting patterns in the snow from Saturday's easterly winds.
The most widespread concern was small, loose avalanches. The top few inches of new snow sluffed easily, producing numerous D1 natural loose dry avalanches when the sun first hit steep slopes. These evolved into larger (D1.5) wet loose by midday on southerly aspects. Increasing cloud cover limited solar late afternoon.
The new snow insulated the wet mush below, preventing a solid refreeze below about 6,000' in last week's wet grains. At mid-elevations, we got frequent small collapses/cracking about a foot thick - this was from the storm interface crust (4/11 crust) collapsing on wet grains below it. As we gained elevation, this sign of instability went away - the wet snow below the new snow was frozen harder.
Noteworthy avalanche activity from last week: Several D2 wet slabs about a foot deep, and a D2 full depth glide avalanche on a small terrain feature. These avalanches were on mid-elevation southeasterly aspects.
We felt comfortable skiing steep terrain where wind drifting was minimal and where the 4/11 crust was frozen and supportive. We made a plan to avoid high, steep due north terrain where we had the most uncertainty for lingering persistent slab issues, given the minimal warming that these slopes saw last week.
Snowpack, Avalanche, Weather Images:
Travel Details
Region:
Outside of the Advisory Area
Route Description:
To 8600'
Activity:
Skiing
Snowpack Details
Snowpack and Weather Details:
Terrain
Elevation of observation:
3500-5000 ft
5000-6500 ft
Above 6500 ft
Aspect(s) of observation:
N
NE
E
Red Flags:
Avalanches from the past 2 days
Collapsing / whumpfing noises
More than a foot of new snow or heavy snowfall rates (>1"/hr)
Rapid or prolonged warming
Rollerballs / pinwheels
New Snow in the past 24 hours:
10.00in.
More comments about the snowpack and weather:
Snow surfaces got moist on all but high NE - NW aspects and mid/low N aspects. Last week's warmup left a supportive melt-freeze crust (4/11 crust) at upper elevations. Crust was softer and collapsible at mid elevations - still refreezing. We didn't travel on high, due north aspects, where I expect the 4/11 crust doesn't exist.
Blowing Snow:
Previous
Wind Speed:
Light (Twigs in motion)
Sky Cover:
Increasing clouds
Highest Precipitation Rate:
No Precipitation (NO)