Public Field Report

Observation Details

Signs of Unstable Snow

Observations

Toured up near the western portion of Mushroom Ridge today. Pretty gnarly 1.5 inch thick surface crust in the new snow on solar aspects - big time survival skiing on the way out. Weather was clear and cold in the morning, then transitioned to partly cloudy around 11:30 AM. I dug around on a couple different aspects - NW (300 degrees) and SE (150 degrees), both at 9300 ft. On the NW aspect, HS was 190 cm and I got an ECTN24 on the layer of near surface facets down 45 cm from the surface. I did a PST as well and got a result of PST 20/100 with a full propagation to the end. I performed a second ECT and received a similar result as the first one - ECTN23 on this same layer. Not sure how to explain this discrepancy between the tests, but nevertheless it did not change my travel plans. On the SE aspect, HS was 125 cm and I was able to get the consolidated new snow (about 25-30 cm on this aspect, still dry under the crust) to propagate in an ECT (ECTP11). The slab failed on a previously formed, rather slick ice crust. I also got a pretty big collapse (on a similar slope down the ridge from my pit) when I stepped out of my skis. When this new snow on solar aspects is inevitably turned to wet slop once it warms up, it seems like it has a prime surface to slide on, or perhaps propagate across. I avoided all avalanche terrain on my tour today, despite my ECTN results. Impossible to ignore a PST result of 20/100 and the widespread natural avalanche activity that has occurred over the last few days.