In Europe they have mini-tornadoes. There was a time in my callow, formative years as a storm chaser when I was unaware that there was such a thing, but one learns. Besides, even veteran American chasers could make the same mistake as I, and probably have done so many times. From the reports, photos, and videos I’ve seen, a mini-tornado so closely resembles a standard-issue tornado in appearance and effect that here in the United States, most chasers would find it impossible to tell the difference.

However, Europeans–newscasters and reporters in particular, who are largely responsible for disseminating the mini-terminology–are more discriminating and not easily impressed. In Europe, it seems that anything less than a Great Plains-style wedge isn’t considered a full-fledged tornado.

Not that wedges are a common occurrence across the pond. The perspective I’ve described appears to be based not on great familiarity with tornadoes, but rather, on a paucity of experience with them other than what is gleaned through viewing videos of the mile-wide monsters that stalk the American prairies. Now those are tornadoes! Compared to them, a trifling, block-wide vortex is … eh. Small change.

Plenty of U.S. chasers would take exception. The problem is, no mini-tornado criteria have been established that could provide a basis for arguing that probably 99.9 percent of mini-tornadoes are simply tornadoes. Not that at least one attempt hasn’t been made to provide such criteria. Back in 2006, in a thread on Stormtrack, I myself presented a plausible set of determinants for mini-tornadoes, complete with a damage-rating scale, and I’m surprised that the NWS never adopted it. Follow my logic and you’ll see for yourself that true mini-tornadoes are a phenomenon few Europeans, let alone Americans, ever encounter.

Mini-Tornado Criteria

A true mini-tornado must meet the following standards:
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•  It is five feet tall or less. Of course, this implies an extremely low cloud base. You’d have to squat in order to get a decent photo.
•  Width: Two feet or less.
•  Human response: You feel a strong urge to say, “Awww, ain’t that cute!” You want to pet it and maybe even take it home with you and give it a nice bowl of debris.
•  The synoptic conditions can be contained within five city blocks.
•  Overshooting tops can be viewed from above by taking an elevator to the ninth floor.
•  Damage (introducing the M Scale):

• M0: Damage?
• M1: No noticeable damage.
• M2: No, there’s no stinking damage. Now go away.
• M3: Okay, some damage now. Card houses knocked over unless securely glued together. Hair ruffled. That sort of thing.
• M4: Now we’re talking damage. Well-built card houses scattered into a lawn-size version of 52-Card Pickup. Ill-fitting toupes snatched away. Nasty things happen when you spit into the wind.
• M5: Inconceivable inconvenience. Securely glued card houses swept entirely away and lofted across the lawn. Well-gelled hair twisted into impressive new designs. You want to get out of the way of this baby.

I hope this helps. Of course, according to these criteria, I suppose the UK has yet to experience a true mini-tornado. Someone should probably inform the press. And none of us should hold our breaths waiting for such an occurrence, because, truth be told, mini-tornadoes are extremely rare.

But not utterly non-existent. The late, talented storm chaser Andy Gabrielson managed to capture on video his personal encounter with a good mini-tornado candidate on May 24, 2010, in South Dakota.* Check out his YouTube video at 1:56, and like me, you too can say to yourself, “What the heck was that?”
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* The footage up to 1:56 is not a mini-tornado.