Observation: Public

Observation Details

Signs of Unstable Snow

Observations

A burst of heavy snowfall occurred during the day, adding 4 inches of cold, heavily rimed snow. Winds began to blow and active snow transport was observed in open terrain. Temperatures dropped quickly after the sky began to break.

At 5,200ft on a northeast aspect the recent rain crust was 3cm thick, and moist snow was found below that. The layer that was previously facets above a crust had turned into moist rounds and appeared well bonded to the crust below it. The rain/snow line from 2/1 appeared to have reached up to about 5,500ft.

Higher up, on a ridgeline of Mt Lillian (~6,100ft) I started getting collapses. These were fairly consistent once on this specific terrain feature. Sometimes they were just small pieces of snow, other times quite a large section of snow would collapse, and drop.
I confirmed the layer as faceted grains sitting over and within a decomposed crust as the culprit. See attached profile from one of the collapsed sections of snow. I also found that layer to hold ability to propagate an avalanche on an ESE aspect at 5,850ft where I didn’t get those warning signs of whumphs (ECTP, 11).

Lots of terrain had been skiied or snowmobile through recently (most likely over the
weekend) without avalanches. There were a fair amount of tracks in the Horseshoe Bowl to the SSW of Diamond Head, below~5.8k.