Observation: Mary Ellen

Observation Date
4/18/2019
Observer Name
Zimmerman-Wall/Nason/Engelhard
Region
Provo
Location Name or Route
Mary Ellen/Mineral Basin
Red Flags
Red Flags
Recent Avalanches
Rapid Warming
Avalanche Problem #1
Problem
Wet Snow
Trend
Increasing Danger
Problem #1 Comments
Widespread wet cycle during last 24 hours. All aspect and elevations. Some point release, some rollerballs and pinwheels. This problem became more pronounced after 12pm. Poor refreeze tonight will make this a problem occur even earlier tomorrow.
Avalanche Problem #2
Problem
Wind Drifted Snow
Trend
Decreasing Danger
Problem #2 Comments
Evidence of previous wind slabs. Some natural, some explosive triggered. Similar characteristics in upper Mineral and Mary Ellen Cirques. 12'x 100-150' wide. Will not be a problem beyond today due to rapid warming and continued settlement.
Comments
Clear skies and rapidly warming temps. Calm to light NW winds after sunrise. Beautiful day in the high alpine. Numerous wet avalanches spotted or created during the day. Any steep rollover would produce large pinwheels with ski cuts and these would entrain and run quite far. Pinwheels would tend to chase you down slope. These did not gouge beyond the MF crust down 30cm from between storms of the prior week. Previous wind slabs across large alpine bowls had run just after storm cleared on 4/17 and all shared similar characteristics. Snowpack test results show where these interfaces exist, but should settle out quickly. As we go into a prolonged period of warm temps and poor refreezes, the snow pack will not consolidate at a consistent interval. The presence of multiple crusts in upper meter of the snow pack provides locations for free water to pool and potentially release wet slab avalanches 30 to 85cm deep. Once these get moving, if the terrain allows, this will become an unmanageable problem very quickly. Timing is everything and monitoring remote weather stations at multiple elevations and in multiple drainages will be critical. Think early starts - Get in, get up, get down, get out.
Photos:
1. Profile from 9600' N. Facing.
2. Evidence of natural avalanches from prior 24 hours in Mary Ellen Gulch of upper AF Canyon
3. Skier triggered wet loose on Northeast Facing 9500' rollover
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable
Coordinates

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