Putting a Spin on Tornadoes

People are dying, lives are being crushed, homes and businesses demolished and entire communities are wiped off the map in seconds. Twisters are nothing new to the United States, particularly the vast plains states. What is new the ferocity and sheer numbers of powerful tornadoes slamming into American communities, even beyond their traditional target areas. It helps to understand historically how they have impacted the United States, how they are formed and what seems to have changed.

To start, the National Oceanic and Atmospheric Administration (“NOAA”) National Weather Service (part of the U.S. Department of Commerce) provides this basic information: “Although tornadoes occur in many parts of the world, these destructive forces of nature are found most frequently in the United States east of the Rocky Mountains during the spring and summer months. In an average year, 800 tornadoes are reported nationwide, resulting in 80 deaths and over 1,500 injuries. A tornado is defined as a violently rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes are capable of tremendous destruction with wind speeds of 250 mph or more. Damage paths can be in excess of one mile wide and 50 miles long. Once a tornado in Broken Bow, Oklahoma, carried a motel sign 30 miles and dropped it in Arkansas !

“Thunderstorms develop in warm, moist air in advance of eastward-moving cold fronts. These thunderstorms often produce large hail, strong winds, and tornadoes. Tornadoes in the winter and early spring are often associated with strong, frontal systems that form in the Central States and move east. Occasionally, large outbreaks of tornadoes occur with this type of weather pattern. Several states may be affected by numerous severe thunderstorms and tornadoes.

“During the spring in the Central Plains, thunderstorms frequently develop along a ‘dryline,’ which separates very warm, moist air to the east from hot, dry air to the west. Tornado-producing thunderstorms may form as the dryline moves east during the afternoon hours.” But on Sunday, May 22^nd, one single tornado in Joplin, Missouri inflicted more deaths – 122 to be precise – than the average annual fatalities for the entire United States. In NOAA parlance, the Joplin storm was an EF-5 generating winds as fast as 200+ miles per hour. And the twisters just kept coming, with 13 more fatalities days later in tornado attacks in Arkansas, Oklahoma and Kansas. Tornado warnings have been issued for east coast regions and parts of the south where such weather patterns are hardly typical. What’s happening here?

The May 25^th Los Angeles Times put the question to some very credible meteorologists: “Warm, moist air from the Gulf of Mexico moved north until it encountered cold air brought south by the jet stream. When the warm and cold air from different altitudes come together, it creates wind shear and circular air motions that lead to a tornado… The air from the south was unusually warm and moist for this time of year, according to Stu Ostro, a senior meteorologist at the Weather Channel. Some experts say this is because waters in the gulf are about 2 degrees warmer than normal for this time of year.” Warmer water in the Gulf is also a precursor to stronger, more virulent hurricanes, not a particularly welcome sign for the coming season.

The Jet Stream, which generally carries cooler air, has move southward just as Gulf water temperatures have risen significantly. This has proven to be a deadly combination. It’s too soon to declare that this confluence of twisters is the result of global climate change heating up the Gulf, but we should keep our eye on this region to see if a longer-term pattern is evolving. If so, that would be strong evidence of such global warming: “It is impossible to link specific storms and weather events toclimate change. But one of the predictions of the climate change models is that we'll be in for more intense storms as average global temperatures climb. That is what appears to be happening, both in summer and in winter.” LA Times.

I’m Peter Dekom, and human beings live on this planet as a guest of Mother Nature, and sometimes she can be a brutal hostess.