The storm taps the Atlantic's moisture-supply and dumps heavy snow over the region. The snow and wind may combine into blizzard conditions and form deep drifts paralyzing some areas. Ice storms are also a problem. Mountains, such as the Appalachians, act as a barrier to cold air trapping it in the valleys and nearby low elevations. Warm air and moisture moves over the cold, trapped air.
Rain falls from the warm layer onto a cold surface below becoming ice.
Along the Gulf Coast and Southeast This region is usually doesn't get much snow, ice or freezing temperatures. Once in a while, though, cold air penetrates south across Texas and Florida, into the Gulf of Mexico. Temperatures fall below freezing, killing tender vegetation, such as flowering plants and the citrus fruit crop. Wet snow and ice accumulate on trees with leaves, causing the branches to snap under the load. Motorists are unsure how to drive on slick roads and there can be a lot of traffic accidents.