Professional Observation

Observation Details

Signs of Unstable Snow

Several Natural avalanches were observed in the Mammoth area today. these likely occurred during the main loading event Tuesday/Wednesday.

The first slide I observed was in the Main Avy path in the Sherwins. this appeared to have gone fairly large, D2.5+

The second observed avalanche was lookers left of Hammil bowl on the Mammoth crest. This path had filled back in and no debris was visible from my location making estimates of size difficult.

Snow Stability

Key Points

I toured from Tamarack up to red cone ridge this afternoon to get a quick survey of the area and to dig in and get a look at how the old snow is adapting to the new load.

the weather was spectacular today with sunny skies cool temperatures and light winds out of the NE. Some wind transport was visible along the crest while making my way up the skin track but overall wind speeds felt pretty light today.

As I approached treeline, prior to hitting the ridge I ventured to a small rollover and initiated a localized collapse with an audible whumph. I decided to dig in here to get a look at the snowpack.  snow depth at this location was 140cm and typical of what we have been observing in areas that still held snow from our early storms in Oct/Nov. The new snow from last weekend is setting up well and is fairly right-side up. However, the old snow is primarily composed of large-grained weak facets and hard crusts. Test results confirmed this interface as our layer of concern and highlighted the fact that in areas with this structure Persistent slab avalanches are certainly still possible and have the potential to be large. (CT13 SC @35cm, ECTPV @35, PST 30/100 @35cm) See Pit info for more details.

Overall it was a good day out, I am still a bit wary of the new old interface and decided to stick to low consequence terrain today but I must say it is nice to have some decent coverage after such a dry November.