Roadside Dust Devil

July 16, 2019


Photographer: Rebecca Roush 
Summary Authors: Rebecca Roush; Jim Foster

This swirl of dust caught my eye as I was driving through central Washington several weeks ago. Dust devils may take shape after sunlight sufficiently heats the surface, if the lower atmosphere is convectively unstable, forming a weak updraft. Their rotating column of winds is usually just strong enough to lift the sand, dust, salt or debris that they entrain. Like this one, most are less than about 100 ft (30 m) in diameter and last for only a minute or two. They’ll disappear once the updraft is lost or if surface features (stand of trees, large hill, etc.) disrupt their movement. Photo taken during the afternoon of May 31, 2019.

Photo Details: Camera: Canon PowerShot SX280 HS; Exposure Time: 0.0010s (1/1000); Aperture: ƒ/5.6; ISO equivalent: 160; Focal Length: 32.8mm.