Weatherz School: Dust devils and whirlwinds
When one thinks of a “dust devil,” you might picture a hot desert rather than northern Minnesota. But, this weather phenomenon can happen here at home.
You may have seen an incredible video that circulated earlier this summer when a fast pitch tournament in Eveleth briefly paused for a dust devil. Then, just as quickly as it arrived, it came to an end. How did a quiet day on the diamond take such a dramatic turn?
Dust devils typically form on clear, hot, dry afternoons. It begins with the sun heating the ground. Low pressure forms from rising air. As air rushes in to fill the low, circulation increases. The process is self-sustaining. Dirt gets picked up and makes the rapidly rotating column of air visible.
In Eveleth, the dirt from the baseball diamond made it the perfect place for a well-defined dust devil. This remarkable display never lasts long. Cooler air gets wrapped into it, and as the temperature difference balances out, the circulation dies.
In order for it to be considered a dust devil, you need dirt or debris to make it visible. Otherwise, it’s called a whirlwind. Rhonda Stewart captured a whirlwind on her property in Tamarack in June. The video starts calm, then the scene explodes near a fire pit. Among the items tossed around is an 80lb bench. The whirlwind briefly becomes visible as it crosses the dirt road, then it disperses as it moves toward the tree line.
Whirlwinds and dust devils are rare in the Northland, but possible under the right conditions, which come with the territory of hot, dry summer days.