Gunnison Backcountry Avalanche Forecast Fri, Dec 18, 2020 at 7:51 AM Issued by: Bo Torrey Danger Rating Friday and Saturday Above Treeline Considerable (3) Dangerous avalanche conditions. Cautious route-finding and conservative decision-making essential. 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 Dangerous condition exist. You can trigger avalanches that break at the ground on a variety of slopes from west through northeast to southeast. In these areas, recent winds drifted snow to created thick slabs 1 to 2 feet deep. The danger is greatest in the western portion of the zone where more snow has fallen over the last week. Treat any steep slope where you see evidence of recent wind loading as suspect. Obvious signs of recent wind loading are smooth rounded pillows of snow, cracking and collapsing in the surface snow, and small drifts on the lee side of ridges or trees. Investigate all steep slopes carefully before riding. If you trigger an avalanche today it can be large and dangerous. You can avoid avalanches by traveling on low-angle slopes less than 30 degrees that are not below or adjacent to steeper slopes. Avalanche Problem Persistent Slab Aspect/Elevation: N,E,W,NW,NE,SE; All elevations Likelihood: Likely Size: Large - Small 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 Fri, Dec 18, 2020 at 8:09 AM Issued by: Bo Torrey Specific avalanche conditions vary slightly across the Central Mountains but the possibility of triggering a large dangerous avalanche exists in each zone. New snowfall and strong winds have created fresh drifts over a very weak snowpack. Natural and human-triggered avalanches have been reported each day since last Friday. Several large natural avalanches observed on Wednesday and Thursday highlight the sensitivity of our weak snowpack. Before last week’s storm we had plenty of weak snow on the ground across the Central Mountains. Now it's all about the slab. In areas where you find a stiffer thicker layer of new or recently wind-drifted snow at the surface you can trigger dangerous avalanches. These areas are most likely to be on northerly and easterly-facing slopes in the Central Mountains. In areas that have received less snow or wind-drifted snow there is not a cohesive slab to present any immediate avalanche danger. A rider triggered and was caught, carried, and seriously injured in an area in the western portion of the Gunnison zone on December 15 in one of those likely spots for slab formation. The accident occurred on a northerly-facing slope where there is plenty of weak old snow, in an area that received a health dose of new snow over the past week. This accident highlights that you should avoid northerly and easterly-facing slopes in the western half of the Central Mountains and also highlights what can happen if you trigger an avalanche right now. Avoidance is the key right now and should be pretty straightforward to accomplish. If you are traveling in areas where the snowpack is deeper, or where you experience cracking and collapsing, or find recently wind-drifted snow you should avoid steep slopes and stick to terrain with a slope angle less than 30 degrees with no steeper avalanche slopes above you. If you are traveling in the thinner areas of the zone where the snowpack is less continuous, most likely in the east, and slabs are not as well developed you should assess every slope for a slab over weak layer combination and pick your slopes carefully. If you want to completely avoid avalanches you can always stick to wind-sheltered lower angle terrain no matter which side of the zone you are on.