Observation: NWAC Forecaster

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Weather Summary

Cold temps first thing in the morning, slowly warmed up during the day and in the sun. Observed moderate and intermittent blowing snow from E winds on the ridgeline of Rock Mtn in the morning, but then winds diminished.

Avalanche Observations

Map of listed avalanches:

Snowpack Observations

We started early, and ascended and descended a non-standard route that avoided danger from steeper slopes in the sun above. A thin, supportable crust was found on top of the recent snow up to about 4000ft then the storm snow became deeper above that.
The interface of the storm snow and early April crust was moist up to around mid 5,000ft and then became dry. At 5,700ft we found about 30" of storm snow above the crust, and were able to get failures with compression tests at two different storm interfaces. One was down about 1ft, and the other was down about 2ft. None of these tests were sudden, but they were planar.

Above 6,000ft I was able to make out some slightly weaker old snow just above the crust. It looked like there had been some in-storm wind slab activity off the north face of Jim Hill summit pyramid, but evidence was obscured from newer snow and wind. Wind drifting had created very thick slabs in some places, and we found some areas with well over 3ft of storm snow on a slope over the crust due to drifting. Other areas held only a couple of feet or less. The slopes that appeared most suspect were the ones facing southeast, where thick wind drifted pillows were warming in the sun. We largely stayed back and above these slopes from the safety of the ridgeline, but did kick a small cornice without results.

Snow surfaces remained cold and dry in the shade during the day at upper elevations, but anything in direct sun became moist and sticky after a few hours of it. Water dripped out of the trees, and we did see a handful of small wet loose avalanches that occurred during the day. Upon our exit at around 1pm, we hit plenty of sun softened and moist, sticky snow at lower elevations.