* WHAT...Snow and blowing snow. Total snow accumulations of 4 to 7 inches. Winds gusting as high as 40 mph. Visibility could be reduced to less than a half mile at times. * WHERE...Dalton Highway Summits, Fortymile Country, Upper Chena River Valley, White Mountains, and High Terrain South of the Yukon River. * WHEN...Until 4 AM AKDT Tuesday. * IMPACTS...Travel could be very difficult. Gusty winds could lead to areas of blowing snow which could reduce visibility below one half mile at times. * ADDITIONAL DETAILS...The worst conditions are expected along highway summits, especially in locations exposed to the southwest.