I kept being woken last night by sudden blasts of wind against my window. I’d doze for about 15 minutes and then get woken by another sudden blast slamming against the window. The very powerful blasts of wind would only last a few seconds. And the wind seemed to change direction each time. In between blasts there was almost complete calm.
This regime went on all night. And I ended up blearily wondering whether some bodies of air travelled much faster than the air around them, like speeding cars on a motorway weaving in and out of slow-moving traffic. I couldn’t think of any other explanation. I wondered why there weren’t motorway pile-ups of air, as the fast-moving bodies of air ran into the backs of the slow-moving ones.
But in the morning, fully awake with a mug of tea and a cigarette, I thought that there was probably a much better explanation for what I’d been experiencing: strong eddies of spinning air, or mini-tornadoes.
For the most part the wind seems to all blow in more or less the same direction all the time, much like a placid river. But maybe when the wind strengthens beyond some point, the flow of air becomes turbulent, just like a river in flood, and the air becomes filled with eddies (right) as it tumbles over itself. And in these eddies the air is moving very fast, going round in circles, just like in a tornado.
So last night maybe what I experienced was a succession of mini-tornadoes. They were part of a relatively slow moving mass of air, all moving in the same direction. They were like eddies in a river.
They would probably have been invisible. Or less visible than the French tornado of a few days back shown below:
The high winds had made the news. They had not been predicted, it seems.
The Met Office is facing criticism for failing to name a ferocious storm that battered Britain with destructive 95mph winds and another blast of heavy snow.
Thursday’s storm which hit a day after Storm Fionn wasn’t given a name, even though amber and yellow warnings were issued, because the predicted conditions fell just below the criteria…
In Britain, the storm left more than 35,000 homes without power and caused travel chaos as it brought down trees onto rail lines and roads, forced bridges to close and disrupted flights and train and ferry services.
Perhaps it’s very difficult to predict mini-tornadoes. My experience last night was of relatively light winds blowing most of the time, punctuated by brief periods of very high winds. Maybe the 95 mph winds were only found in mini-tornadoes, because the principal prevailing wind was probably not much stronger than 30 or 40 mph.
And perhaps mini-tornadoes would explain why just one tree gets blown down (like the one below) and not the ones next to it. A mini-tornado might only be a few feet or yards in diameter, and the strongest winds within it might be located at one small, single point within it, delivering hammer blows at one single location.
It reminded me that yesterday I’d seen some crows in flight, hundreds of feet in the air, and noticed that they were flying in irregular paths, some going down as the others near them rose. It’s probably hard for birds to fly in very turbulent air. One moment they’ll be thrown downwards, the next lifted suddenly upwards or leftwards or rightwards or forward or back. Maybe some of them even get their wings broken by sudden gusts.
Anyway, my guess is that while the Met Office could predict the average wind speed (which certainly wasn’t 95 mph), they couldn’t predict the mini-tornadoes or the high winds inside them.
One simple physical explanation for the mini-tornadoes might be that if the average speed of the wind cannot be increased over a large geographic area, the wind speed can be raised locally in the mini-tornadoes. So the kinetic energy in the prevailing wind might be ½mv², but be ½mV² inside the mini-tornadoes, where wind speed V (95 mph) is a lot bigger than v (30 mph). In this manner the kinetic energy of the entire air mass could be raised without raising the prevailing wind speed, by having small localised “hot spots” of fast-moving air.
Anyway, if nothing else, it goes to show that we don’t understand very much about weather and climate, and that includes the Met Office.
And I’m going to be dozy for the rest of today: I didn’t get enough sleep last night.