Except for extreme southern portions of the United States,
almost any area east of the
Rocky Mountains can experience freezing rain.
The area most frequently hit by
freezing rain extends
over a broad region from
Texas northward to
Minnesota and then eastward into the Middle Atlantic states
and New England.
Freezing rain generally does not fall west of the Rockies because one of the key ingredients is missing; shallow arctic air, which is unable to flow over the mountains. The only regions in the West that experience freezing rain are near the Columbia River in southern Washington and northern Oregon. Freezing rain occurs when cold air gets caught in the river valleys and warm moist Pacific air rides over top, creating a favorable set-up for freezing rain.