Backcountry Avalanche Forecast North San Juan, Colorado
Archived - Expired
Mon, Feb 1, 2021 at 7:06 AM
Issued by: Mike Barney
	
Monday and Tuesday

Above and Near Treeline - Considerable (3)
Dangerous avalanche conditions. Cautious route-finding and conservative decision-making essential.
	  	
Below Treeline - Moderate (2)
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully.
	  	
Summary

We have seen large and dangerous natural and human triggered avalanches at upper elevations on northwest to north through southeast aspects in the last few days.  Slopes that fit these descriptions that have not yet slide should be treated with extreme caution. Below treeline slopes may not propagate as wide, but avalanches will be deep and can be dangerous if they push you into trees or a terrain trap. You are most likely to trigger these avalanches on steep convex rolls or in previously wind affected open areas.

Low-angle terrain well away from steep slopes or lower elevation terrain less steep than 35 degrees can provide safer riding options. 

Avalanche Problem
Persistent Slab
All Aspects and Elevations except S -> W Below Treeline
Likely
Small to Large

What You Need to Know About These Avalanches

Persistent Slab avalanches can be triggered days to weeks after the last storm. They often propagate across and beyond terrain features that would otherwise confine Wind and Storm Slab avalanches. In some cases they can be triggered remotely, from low-angle terrain or adjacent slopes. Give yourself a wide safety buffer to address the uncertainty.

Forecast Discussion
Mon, Feb 1, 2021 at 7:50 AM
Issued by: Mike Barney Statewide Weather Forecast  

Since Tuesday, we have had 51 reported natural and skier triggered avalanches large enough to bury and kill a person. Most of these avalanches have been near and above treeline. Yesterday skiers in Bear Creek near Telluride remotely triggered a large avalanche from about 100 feet below a northwest-facing slope above treeline. On Saturday, a snow machine near Silverton also remotely triggered a large slide but on a southeast aspect above treeline. In the La Plata Mountains, we have reports of numerous large natural avalanches on mostly northeast to southeast-facing slopes, and yesterday above Ophir, southeast-facing terrain was avalanching naturally midday. North San Juans have seen far more activity in the last few days than the Southern San Juans Mountains.

Winds from southwest to northwest have been the main culprit in tipping the scale in our snowpack. Slopes facing northwest to north through southeast have been the most reactive with recent natural activity and human triggered slides. Be wary of these aspects at all elevations, especially near and above treeline where slabs have been breaking far and wide.  

We are taking below treeline terrain off our distribution rose for the persistent slab avalanche problem today. It is not the most likely place to trigger these avalanches. However, you can still trigger large avalanches at lower elevations, especially on slopes steeper than 35 degrees where the wind has drifted snow recently on convex rolls or other open areas. 

Slopes in the direct sunshine today will be wet on the surface, and pushing small loose wet avalanches will be possible. Avoid sticky wet snow on steeper slopes to avoid these avalanches. Wet snow is heavy and hard to escape if you are caught.