The Three Hills, AB tornado of June 2, 2017

What happened?

On June 2, 2017, thunderstorms were forecast over much of Alberta. With increasing shear, thunderstorms would become progressively more organized and severe throughout the day.
Model simulaitons displayed instability in the 1000 J/kg range, but different models disagreed as to whether the stronger shear was to be juxtaposed over the instability.
By late afternoon, a quasistationary convergence line sat over central Alberta, and storms moved overtop this line.
It appears that this convergence line, in combination with the underforecast upper-level winds, provided a strong enough shear environment for both mid- and low-level rotation. As a result, a tornadic supercell emerged near Three Hills, resulting in one of the most iconic thunderstorm images of 2017.
The imagery from this event is presented here.

Satellite images

RADAR images

Surface analyses

Model output


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Last update to this page: November 7, 2017