Above 7500 feet, deep persistent weaknesses lie in the snowpack. Large to very large avalanches were occurring naturally on this layer earlier in the week. The danger rating has lowered to Moderate because these slides are not expected to occur naturally, however it is important to understand that they could still fail to the weight of a single person is some areas. Determining which slopes are more likely to fail is very difficult and limiting exposure to low angle terrain is recommended for safe backcountry travel. A chance for shallow wind slabs to be triggered also exists at the high elevations. Avalanches below 7500 feet are not expected today. On tuesday a snowmobiler in the Wyoming range narrowly escaped tragedy when he triggered a deep slab that buried him under five feet of debris. His partners located and uncovered him in 20 minutes with transceivers and shovels. He sustained minor injuries.
Above 7500 feet, dangerous persistent deep slabs up to five feet in depth could be human triggered on a variety of aspects. These hard to predict slabs could release to the weight of a single person, propagate long distances, and are likely to carry severe consequences.
Dense wind slabs lie at high elevations in areas prone to wind loading that could be triggered today with depths up to a foot. These slabs have been formed by strong southwest to west winds that are forecast to become northwesterly today. Once initiated, movement of these slabs could cause failure in the deep persistent weak layers.
( Discussion is generated from the previous day's afternoon forecast. )Periods of light snow are forecast to continue through Friday. Accumulations will be on the light side. Temperatures in the mountain should stay in the twenties through the day before colder air moves in Friday evening. Strong west winds overnight are to lessen throughout the day and veer to the northwest in the afternoon. The general avalanche hazard will be Moderate above 7500 feet. It is paramount that backcountry travelers understand that it is rated Moderate because the sensitivity of these dangerous slabs has lessened, as evidenced by the lack of natural activity occurring the last few days. Moderate means that a load is needed to cause the failure and the potential still remains for a single person to trigger a large or even very large dangerous avalanche. Staying off of steep avalanche terrain and choosing lower angle terrain is still the smart choice this year. Avalanches below 7500 are unlikely tomorrow.
