Colorado - Gunnison Region Archived Backcountry Avalanche Forecast Thu, Jan 21, 2016 at 7:27 AM Issued by: Jason Konigsberg Today, Above and Near Treeline Considerable (3) - Dangerous avalanche conditions. Cautious route-finding and conservative decision-making essential. Today, Below Treeline Moderate (2) - Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully. Summary As the latest storm clears the state snowfall has ended and winds are decreasing. Most of the zone picked up between 2 to 4 inches overnight and into this morning but areas around Kebler Pass and Gothic picked up about a foot of snow. Winds are lighter than yesterday but the speeds are still strong enough to move snow and will have no problem drifting this snow into sensitive slabs 2 to 3 feet thick on easterly aspects. Northeast to east through southeast aspects are where you are most likely to trigger a Wind Slab avalanche. Any avalanche triggered in the new wind-drifted snow may step down to more deeply buried weak layers resulting in a much larger and more dangerous avalanche. New snow over the last week is sitting on top of very weak snow that formed during the mid-January stretch of cold and clear weather. An avalanche that steps down to this layer will be larger enough to bury a person. Observations around the Crested Butte area show that triggering deeper avalanches is still possible. Travel cautiously in the mountains today and pay careful attention to avoid areas of wind-drifted snow. As the storm clears the area the snowpack will need time to adjust to the new load and patience and avoidance of steep wind-loaded slopes will be necessary. Areas south of Crested Butte are at more of a MODERATE (Level 2) avalanche danger. Although there is less snow in these areas be wary of any areas of wind-drifted snow. Avalanche Problem - Wind Slab Where: NE - S All Elevations Probability: Likely Size: Small - Large Wind Slab avalanches release naturally during wind events and can be triggered for up to a week after a wind event. They form in lee and cross-loaded terrain features. Avoid them by sticking to wind sheltered or wind scoured areas. Avalanche Problem Persistent Slab Where: N-E-S Above and Near Treeline Probability: Possible Size: Small - Large 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 Thu, Jan 21, 2016 at 10:38 AM Issued by: Jason Konigsberg Continued wind and snow keep the avalanche danger CONSIDERABLE (Level 3) across the Gunnison Zone. Yesterday areas around Kebler Pass and Gothic received about a foot of snow with strong winds. Areas closer to the town of Crested Butte received 6 to 8 inches. The Taylor Park areas received between 3 to 5 inches. The areas that received upper-end amounts with wind are seeing large slabs form from wind-drifted snow. The southern parts of the zone that received lower-end amounts will see smaller slabs and a more MODERATE (Level 2) danger. Reports have come in every day since the series of storms started last Thursday of natural and human-triggered avalanches. Most of the avalanches are breaking on a layer of well developed facets that formed during the clear and cold weather in mid-January. The strong wind during the storm easily drifted enough snow onto slopes to overload this weak layer and cause widespread avalanches. A week ago our focus was on small Wind Slab avalanches that could potentially step down to deeper weaker layers resulting in an avalanche large enough to bury a person. This is still a concern, but the wind-drifted slabs on top of these weak layers are now thick enough that avalanches triggered within wind-drifted snow are large enough on their own to cause serious problems. This layer of facets that lies underneath of the last week's storm snow is our new persistent weak layer and will be discussed in future forecasts within our Persistent Slab avalanche problem. Settled weather is forecast for Thursday and Friday and storm instabilities, including problems with newly wind-drifted snow, will settle out but the layer of mid-January facets and associated Persistent Slab avalanche problems will remain. We will still monitor our weak basal layers but the newly buried weak layer is closer to the surface and it will be much more susceptible to a human trigger. The most likely place to trigger a Persistent Slab avalanche is near and above treeline on north to east through south aspects. I would not disregard any of the aspects mentioned above but I would pay extra attention to east and southeast aspects. East and southeast aspects, especially near treeline, had previously shallower and weaker snowpacks prior to the parade of storms. These aspects also may have a thin melt/freeze crust capping the mid-January facets. Thin crusts surrounded by facets are notorious for allowing avalanches to propagate much wider than expected. In the Gunnison zone, especially around the Crested Butte area, we also have many avalanche paths that slid during the Christmas avalanche cycle. The snowpack in these areas resembles an early season snowpack which is thin and weak. We will have to continue to monitor these areas as this weak snowpack will not be able to sustain much of a cohesive slab before avalanching again. The bottom line is, we need to be stepping back our terrain choices with a newly buried weak layer. Avoidance of heavily wind-loaded slopes will be important. Assessment of the new snowpack structure and the new weak layer/slab combination will be necessary to determine how reactive our new problem will be.