Northern San Juan
AvalancheJosh Jespersen · Jan 12, 2023 · Northern San Juan
Weather
On 1/12 the wx in Ophir was incredibly beautiful with blue skies and warm temperatures. NTL/BTL got quite warm during peak sun, and although there was new snow coming off of geology ATL on solar aspects it is hard to say how warm it got up there as a L/M wind kept it cooler up high.
Snowpack
We were mostly on solar slopes along the Ophir Pass Road which had soft surface snow in the morning that got somewhat gloppy in the afternoon. We consistently found persistent grains on S and SW slopes NTL near the ground. The snowpack was deeper than expected with depths ranging from 60cms to 140cms and moderate results were initiated with CTs on that PWL. ECTXs were observed, but PST results were between 20 and 30 over 100 when testing the 11/29 layer.
Avalanche
A very large and striking avalanche took place at some point in the afternoon. We could only observe the crown and one flank of the main avalanche on the south facing slopes of Silver Mountain above Staatsburg Basin, but could see all of what seemed to be a connected avalanche in the Badger path on a SW slope. Using Caltopo to measure the crown above Staatsburg, it is almost a half mile wide and the whole avalanche ran at the ground on what must have been persistent grains. It is hard telling if the two avalanches are truly connected, but if you look closely at the photos they appear to be. I could not observe into Staatsburg Basin, but judging by the size of the crown I would imagine that avalanche to be at least a D2.5 in size. Badger ran for almost 2,000 feet. Whether or not these avalanches were instigated by the afternoon heat is hard to say, but they both ran on the ground on S and SW facing aspects ATL on what must have been persistent grains.