About the Forecasts
To create an avalanche forecast, the Northwest Avalanche Center forecasters distill snowpack information gathered from a variety of sources and try to paint a regional picture of snow layering and related stability which can be found in each day's avalanche forecast. Avalanche information comes from snow and weather observations made by NWAC forecasters, NWAC professional observers, as well as other snow safety professionals and back country travelers. Professional ski patrols, highway avalanche control programs, national park and forest rangers, ski guides and others are in relatively constant contact with NWAC staff throughout the winter in order to ensure that the best and most pertinent snow safety information is made available.
Avalanche Warning, Watch and Special Bulletin
Want to the know the criteria for NWAC to issue an Avalanche Warning, Watch or Special Avalanche Bulletin?
Please see this document: NWAC Warning, Watch and Bulletin Definitions
Descriptions of the 9 avalanche problems used in the US and links to detailed information on the problem, formation, patterns, recognition, and avoidance strategies are provided by the Colorado Avalanche Information Center and can be found here.
Avalanche problems explained by the National Avalanche Center in a short video: