Winter is usually the quiet season for North American tornadoes, so the residents of Kansas, Oklahoma and Texas were rather taken aback when as many as 40 twisters whipped across the high plains last week. Some of the tornadoes produced spectacular golf-ball-sized hail stones, and one even tore up ears of corn and flung them back down encased in little bullets of ice.
In this case the tornadoes and associated high winds were forecast well in advance, but they still managed to cause plenty of damage. An oil-field servicing plant in Texas was destroyed, roofs were ripped off and power lines were sliced, leaving 47,000 people without power in Texas and Oklahoma alone.
So what was behind the weird weather? In this case it was brought about by a combination of unusually warm waters in the Gulf of Mexico, which fed lots of energy and moisture into the atmosphere, and a juicy storm riding along on a powerful jet stream.
This low pressure system, known as storm Ajax, plastered the southern Rockies with snow and created blizzard conditions over parts of the high plains. But it also spawned huge thunderstorms further south, and it was from this high energy environment that the tornadoes emerged.
To have a tornado outbreak so far inland, and across such high ground, is unprecedented at this time of year. The strong El Niño conditions in the Pacific may have contributed by injecting more energy into the jet stream, and altering its usual path, but El Niño alone can’t be blamed – sometimes the weather is just plain freaky.
