A major winter storm is sweeping across the United States, triggering alerts from the National Weather Service due to heavy snowfall and dangerous travel conditions. The Northern Rockies are preparing for up to five feet of snow, with the possibility of blizzard conditions in northeastern Minnesota. Idaho and western Montana are under winter storm warnings, with 20 to 50 inches of snow expected in higher elevations, accompanied by wind gusts up to 60 mph. Even Hawaii's highest summits are facing winter storm warnings, with forecasts of 12 to 18 inches of snow and wind gusts potentially reaching 110 mph.