Winter Weather Advisory:
This is the snowfall criteria map for a Winter Weather Advisory.
In addition, all zones have a blowing snow criteria as follows:
When one of the following combinations are forecast to occur for at least 3 hours:
1. Sustained wind or frequent gusts 25 mph or greater and visibility less than or equal 1/2 mile (but greater than 1/4 mile)
2. Visibility is 1/4 mile or less, and winds are at least 25 mph but less than 35 mph
There is also a multiple event criteria for all zones as follows:
Mixed precipitation or multiple winter weather events even if only one precipitation type meets or exceeds advisory criteria, but remains below warning criteria (this may include wind and/or wind chill).
Just like the Winter Weather Advisory, there is a rule that applies across all zones. Namely:
Mixed precipitation or multiple winter events, even if only one precipitation type meets or exceeds warning criteria (this may include wind and wind chill) .
This one is self-explanatory. Any ice amount greater than the amount defined for the Freezing Rain Advisory qualifies as an Ice Storm Warning.
Wind Chill Advisory / Warning:
There is no map for the Blizzard Warning. It is standardized across not just Alaska but the entire U.S. The criteria is as follows:
When forecast to occur for at least 3 hours: Blowing snow (with or without falling snow) reducing visibility to < 1/4 mile when accompanied by sustained wind or frequent gusts > 35 mph.