North Routt: Buck Mtn

Small to Large Persistent Slab NW-SE Possible across All Elev

For the last 72 hours winds were calm. That changed overnight. Winds started ramping up yesterday evening and are forecast at 10 to 20 mph today from the west-southwest with stronger gusts especially in the Front Range. In most of the Northern Mountains there is at least 6 inches of snow sitting on windward slopes just waiting to be transported. Thick slabs of snow will form on leeward slopes. With the new loading, natural avalanches are possible. They can break on a recent shallowly buried faceted layer or deeper ones that were buried in early December.

The increase in wind loading has increased the avalanche danger. There is some uncertainty as to if this loading today will lead to the forecast dangerous conditions. In the past when we have had snow sitting around for a few days without wind, and then a sudden bump in winds, we see natural avalanches. We will see if this pans out today. Use caution if you are traveling in wind-drifted areas and give slopes a wide berth if you see active loading. If the wind forecast doesn’t verify or less snow is drifted than forecast, you should still use caution as older wind-drifted slabs sit on buried weak layers in many exposed places.

Watch for fresh wind-drifted snow on steep slopes. This is where you are most likely to trigger a large avalanche. An avalanche that you trigger could break much deeper than this wind-deposited snow. Identify wind loaded slopes by the smooth and rounded look to the snow surface. These dangerous slopes are most often located directly below ridgetop. Cornice formation above the slope is another sign of previous or recent wind loading.

Don’t let your guard down as you drop down in elevation to sheltered areas. Steep slopes with more than a foot of recent snow should be carefully evaluated. Stick to lower-angle slopes if you observe obvious signs of instability such as shooting cracks or sounds of the snowpack collapsing.