Mini-Tornadoes: Defining a Microscale Mystery

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: . •  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?" --------------- * The footage up to 1:56 is not a mini-tornado.