Northern San Juan
SnowpackBill Nalli · Dec 23, 2019 · Northern San Juan
Weather
Transition day before the storm. Periods of broken clouds and sun gave way to full overcast and flat light. Slightly colder than the last few days. The wind picked up mid day and was gusting into the 30's. Snow was blowing around but with not much available for transport, not really loading into new slabs.
Snowpack
Went up high to get more information in the alpine. The wind really had its way in this area above treeline. All aspects are rough. S and W are stripped bare and all the others are a mix of stiff wind board, sastrugi, and deteriorating wind crust. The wind slab of concern from last week is very strong and I found none in this zone that I thought were able to fail with the weight of a person. My one snowpit on a NE test slope was very deep. 160cm of 1F to P hard rounds over 15 cm of rounding depth hoar. It would take a massive load to overload this strong slab to make it fail. The problem is that as I scanned across the range, I can see other locations where this slab is not so thick and there are likely spots where a rider could trigger this hard slab. These spots are also not where you want to get caught per bad consequences. Near and below treeline the persistent weak layers have gained strength. Not fully able to write them off just yet but they also will need a significant load to reactivate. The current snow surface below treeline is now small faceted grains on the north half of the compass and thin crusts on the south. This will be the most immediate layer of concern with the new Christmas load.