Winter Storm in Missouri Headwaters, Montana

DOT reported a foot of new snow in the Cardwell area. Public report near Whitehall estimated 18 inches new snow.

A stout closed low over Manitoba swung a shortwave around its western periphery and then southward toward the Northern Rockies Feb 16. The wave stalled over MT, resulting in a strongly cyclonic flow aloft, while the main upper disturbance exited eastward.. This allowed for a long duration snow event that lasted into the 18th.

After this system cleared out, a strong surface high resulted in another period of extreme cold. This episode will also serve as the location for additional extreme cold highlights from June 16 through the morning of the 19th.