Tornado watch

By Al Lowe
Contributor

It seems to me and to a lot of folk my age, that tornadoes are a lot more common then they used to be. Perhaps it is only better reporting. But when I was a boy in Southern Ontario, I hardly ever heard of a tornado in the province. Now they seem to be happening quite regularly.
Tornadoes and hurricanes have some things in common. Both are masses of air flowing on a circle, and both have intense low pressures at their centres. Hurricanes may be 200 or 300 miles across. They are usually formed in tropical or sub-tropical areas. They build up over the sea, and get more intense as they travel over the oceans. Once inland, however, they start to decay, but they can cause immense, widespread damage in the meantime.
Tornadoes are quite small, usually not more than 500 or 600 metres across. However, in the immediate path of a tornado, the destruction can be very much greater than that of a hurricane. Just remember the TV pictures you have seen on the past year or two - homes and buildings just demolished, cars hurled around like toys, trees uprooted and flung away - this is how a tornado acts.
The weather conditions for the formation of a tornado are something like this. A lower layer of hot, humid air meets an upper layer of cold dry air. The combination often causes a rapid upward flow of the hot air. The moisture in this hot air condenses, releasing even more heat, so the warm air rises even faster. This is the type of condition which builds up violent action in the sky, with rapid movement of air and clouds and crackling thunderstorms. In Northern Ontario, the possibility of all this developing into a tornado is here, but it is not really very common.
In the American midwest, however, the possibility is quite high. Very hot moist air from the Gulf of Mexico flows inland and meets cold air from the northern States and Canada. Tornadoes can form very quickly and often in that area. In Oklahoma, for instance, the average is over 400 tornadoes a year.
The very rapid upward rush of air causes fast movement in the air around it. Winds in a tornado may be up to 300 miles an hour or more. This extremely fast movement of the air causes a 'whirlpool' effect. You have all seen a whirlpool formed in very fast flowing water. In a tornado we have the same effect - a very, very fast whirlpool of air.
The extremely low pressure at the centre of the tornado acts like a giant vacuum cleaner, and sucks up roofs, cars, animals, people and almost anything else in its direct path.
Most folks know that a tornado looks like a huge funnel, under towering black, menacing clouds. The tornado itself is often black, but it may be brown, or even white. The air in the spiral is usually cluttered up with dust, earth, leaves and assorted debris.
In our area, or any other, there is one thing you should all know for sure. A tornado is not something to be fooled with.
If you should see one coming, get down into your basement (or someone else's) as soon as you can. Remember, the destruction is only in a very narrow band, but it can be terrible indeed.