.. and another repost apropos our recent tornado activity:
That tornado didn't kill anyone, but it did happen to rip off the top half of a tree in the front yard of a house I had just signed on to purchase. Miles away from where the talk was being given. What luck.
The big tornado that came through Minnesota about ten years ago, one of the biggest tornadoes ever recorded, resulted in only two deaths because Minnesotans are neither macho nor ignorant of tornadoes. We just go to he basement when we are told.
But the luck of a lot of mid-Americans is not going so well these days. The tornado death toll over the last couple of weeks in in the couple-dozen range. That is not a cyclone in the Indian Ocean or even a Hurricane in the Gulf of Mexico. But it is a lot for tornadoes. We are having a very very bad year, it would seem.
Up here in Minnesota, the cold and long winter we had caused a lot of regular people to question the validity of the Global Warming claims. That is a reasonable question to ask ... if it is supposed to be getting warmer, why did it get colder? The answer, of course, is that year to year weather patterns in a given area will always fluctuate a great deal, so one cannot use one's local experience over one year to evaluate large scale and long (or even medium) term patterns. This is not a question of the nature of climate. Rather, it is a question of the nature of science education. By the time every American is out of high school, they should understand this. They don't, of course. They don't get this any more than they get that the summer-winter seasonal march is NOT caused by the earth moving closer to and farther from the sun.
(And since they don't understand it, their ignorance can be exploited for political purposes. What a shame.)
More frequent and/or more powerful tornadoes in one year may also be a matter of "secular" variation ... as opposed to long term climate change. But this could also be the result of global warming. So, to all those Minnesotans who say "Hey, it was a cold winter, I guess the Global Warming scare is over...," one might respond, equally stupidly, "Yea, but look at all these tornados.... "
There is a video here that shows some of the tornado action over the last day. I find it fascinating that the folks in one part of the video figured that there were no tornadoes around because the view northward from their porch showed clear skies. Meanwhile, a tornado sneaked up right behind 'em, coming from the south! Tornadoes, though, almost always come from the west or the south. Why would they not know this? Is our society that buffered from nature that the basics of which way the wind blows is simply unknown to many people?
Here is an animated GIF of some weather just north of the Gulf of Mexico, showing the movement of energy from the Gulf northwards, in this case causing deadly tornadoes.
(This is from a blog on The Weather Channel)
The fact that tornadoes almost always come from the west or the south in this region is related to what tornadoes are: They are highly concentrated storm energy, and part of a larger system of energy being diffused from the Gulf of Mexico northwards and, because of global wind patterns, eastward. Indeed, this region, the American Midwest and the Southeast, is anomalous in the flow of equatorial energy towards the poles. The southeast should be much dryer than it is, and the upper Midwest should be (probably) a bit warmer than it is (in the winter). But the mountains to the west and the Gulf of Mexico (a hyper-warm body of water) to the south change all that and make things act differently than they might on an idealized planet with fewer obstructions from mountains, oddly placed continents, and other factors.
It is like placing a rock in a stream: The rock may cause the water to roil, to form a standing wave, to form a whirlpool. The rock is a perturbation in the basic, straightforward process of the water running down stream. Turns in the channel, changes in depth, rocks, tree boles angling in from the bank, all of this makes the river current odd and quirky and you get eddies and waves instead of a nice even flow. The odd distribution of continents (in relation to oceans), mountains, etc. do this as well. So we get hurricanes in the North Atlantic but not in the South Atlantic. And we have this thing called the "tornado belt" which moves around from year to year but is generally in this region where the Gulf energy plows northward and eastward across a big flattish area.
Tornadoes happen in mid-America. There is a pattern to when and where they happen, even though the pattern is a little complex. There is a pattern to what happens locally when conditions are right for a tornado. Knowing these patterns should be helpful, just like knowing the traffic patterns related to your commute (or your drive up to the lake) is helpful.
Knowing a bit more about the science could even save your life.
July 18th, 1986 Fridley, Minnesota Tornado (some of the most amazing tornado footage I've ever seen):
Some of the damage caused by this tornado is preserved in a local park.
The real effects of global warming don't start coming out until you apply statistical methods to the data.
E.g. average temperatures are up +2F. Not a terribly noticeable difference but it's there.
Then of course there is observation of local events. I've seen lots more flooding here in RI over the past 6 to 8 years than I had the decades before that.
So we get hurricanes in the North Atlantic but not in the South Atlantic.
Which is why the Brazilian meteorological service tried to insist, for almost a year after the fact, that Cyclone Catarina was not a hurricane (which it was).
Similarly, tornados are rare outside the American Midwest, but they do happen. We had a bad one in New Hampshire a year ago; you can still see some of the damage it did where the path crossed US 4 in Epsom.
In our part of Missouri we tend to be a bit more skittish about tornado warnings (my native wife is a weather channel freak) because the lie of the land makes it difficult to eyeball them, even when they aren't sneaking around under a cloak of rain. In flatter country, I imagine you can afford to be a bit more macho, unless you're unlucky enough to have one touch down right on top of you.
> July 18th, 1986 Fridley, Minnesota Tornado
Video no longer available, apparently?