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Precipitation in the Pacific Northwest into the Northern Rockies; Bering Sea Storm in Alaska

A Pacific storm will bring rain and high elevation snow from the Pacific Northwest into the Northern Rockies. A series of storms are expected to move through the Bering Sea bringing strong winds, heavy precipitation, and elevated water levels from the West Coast to northern Alaska. Read More >

Overview

On June 29, 2019 a surface boundary was located across south central South Dakota. Very strong instability along the boundary was realized when a thunderstorm exploded along it. The thunderstorm updraft stretched energy along the boundary into a very slow moving tornado near Allen, SD.

The tornado was visible for many miles. It was unusual because it only moved within a two mile area, but lasted about 40 minutes. Fortunately, it spun over corn fields most of the time. It damaged a house, blew over a couple of grain bins, snapped power poles, and carried grain bags. The tornado was rated EF-1 by an NWS storm survey team.

More information about the environment of the Allen tornado can be found here. 

Tornado near Allen, SD
Courtesy Chris O.
Tornado near Allen, SD Tornado near Allen, SD Tornado near Allen, SD
Courtesy Gail S. Courtesy Josie D. Courtesy Ang G.
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