Dust devils can be strong! When I was in junior high school in Southern California, I had an encounter with a monster duster. The whirlwind swept through the yard and nearly knocked me down. A student nearby had a notebook full of papers torn from his grasp and sent whirling up 50-100 feet and away.
On my way home that day, I saw the scattered pages from that notebook strewn through a housing tract 1/2 mile away.
I can believe it. This one was at least several stories tall. It only broke up after it incountered a gas station. Looked just like a tornado. Only smaller of course. I'm use to the big swirly ones that just throw a lot of dust around.