Northern San Juan
SnowpackBill Nalli · Dec 7, 2019 · Northern San Juan
Weather
Clouds moved in mid morning but intermittent periods of sun and light NW wind. Mild temps.
Snowpack
Warm temps over the last week have helped with settlement. SE through S, SW and W aspects have strengthened from mild temps and direct sun. Hazard today was LOW on these aspects and a crust exists up to about 12,000'. Small grained facets were observed both above and below it on SE aspects and this may create an avalanche problem once buried with our next storm. Will have to wait and see how the snow and wind pile up in the next 48 hours. The other half of the compass has also strengthened over the last week and the modest snow amounts from the last storm were not enough to overload our main avalanche problem of a dense slab over depth hoar. A pit dug in Commodore Gulch slightly above treeline at 12,000' on a N aspect showed a 100cm P hard slab over 15cm of depth hoar. Long column test showed that this set-up is strong but the column failed and propagated after 28 taps. Where the slab is this thick and dense the weight of a rider seems unlikely to cause failure. The catch here is that the slab is not that thick across the entire slope and if a rider is to find a shallow or weaker spot, failure could occur and propagate into a large enough avalanche to bury and injure you. Higher above treeline, many slopes have been stripped by strong winds and the slabs are not as thick. Avalanches in this zone are likely to be smaller but are still a hazard in consequential terrain.