Northern San Juan

Avalanche

Chris Dickson · Jan 6, 2023 · Northern San Juan

Weather

Beautiful warm day on 1/5, with calm winds picking up to moderate gusting strong by afternoon out of the SW. Rollerballs and a thin suncrust were observed on Wests from a brief period of sun and warming on the afternoon on 1/4. The warm temps and strong sun on 1/5 produced a widespread zipper crust on steeper south-facing slopes by end of day.

Snowpack

The snowpack BTL/NTL in this area is now pushing the 130-150cms mark, with a 4F to 1F midpack slab sitting above 20-40cms of depth hoar in this area. Two persistent weak layers still show reactivity in stability tests (11/29 and 12/28) but harder scores in these tests indicate their sensitivity to triggering is decreasing. Audible whumphs and collapses have become absent since the most recent load.

Avalanche

A widespread natural cycle occurred on the steep south-facing terrain above Ophir during the last storm, with storm slab avalanches running close to the valley bottom off Lookout Mountain and in the Badgers slidepath, with debris and crowns evident under the last 6" snowfall. Sometime during the morning of 1/5 a large natural avalanche (SS-N-R3-D2.5) released on the south-southwest facing slopes above Iron Springs and ran from 12,600' to 10,600' almost making it down to the Ophir Pass Road. This slide had a wide-propagating crown and it released as solar input peaked mid-morning. Another impressive slide was triggered by explosive work from HeliTrax in upper Waterfall Basin below Pilot Knob, with crowns propagating across and around terrain features. Numerous other BTL D1's were observed on NE and NW facing terrain.