Thursday, April 24, 2014
WASHINGTON — Everything had to come together just perfectly to create the killer tornado in Moore, Okla.: wind speed, moisture in the air, temperature and timing. And when they did, the awesome energy released over that city dwarfed the power of the atomic bomb that leveled Hiroshima.
A rescue worker checks the rubble in a residential area in Moore, Oklahoma May 21, 2013 after a massive tornado struck the area May 20. Emergency workers pulled more than 100 survivors from the rubble of homes, schools and a hospital in an Oklahoma town hit by a powerful tornado May 20, and officials lowered the death toll from the storm to 24, including nine children. (REUTERS/Richard Rowe)
An aerial view of destroyed homes in Moore, Oklahoma May 21, 2013, in the aftermath of a tornado which ravaged the suburb of Oklahoma City. Rescuers went building to building in search of victims and thousands of survivors were homeless on Tuesday, a day after a massive tornado tore through Moore, wiping out whole blocks of homes and killing at least 24 people. Seven children died at the school which took a direct hit in the deadliest tornado to hit the United States in two years. (REUTERS/Rick Wilking)
On Tuesday, the National Weather Service gave it the top-of-the-scale rating of EF5 for wind speed and breadth, and severity of damage. Wind speeds were estimated at between 200 and 210 mph. The death count is 24 so far, including at least nine children. The United States averages about one EF5 a year, but this was the first in nearly two years.
To get such an uncommon storm to form is "a bit of a Goldilocks problem," said Pennsylvania State University meteorology professor Paul Markowski. "Everything has to be just right."
For example, there must be humidity for a tornado to form, but too much can cut the storm off. The same goes with the cold air in a downdraft: Too much can be a storm-killer.
But when the ideal conditions do occur, watch out. The power of nature beats out anything man can create.
"Everything was ready for explosive development yesterday," said Colorado State University meteorology professor Russ Schumacher, who was in Oklahoma launching airborne devices that measured the energy, moisture and wind speeds on Monday. "It all just unleashed on that one area."
Several meteorologists contacted by The Associated Press used real time measurements, some made by Schumacher, to calculate the energy released during the storm's 40-minute life span. Their estimates ranged from 8 times to more than 600 times the power of the Hiroshima bomb, with more experts at the high end. Their calculations were based on energy measured in the air and then multiplied over the size and duration of the storm.
An EF5 tornado has the most violent winds on Earth, more powerful than a hurricane. The strongest winds ever measured were the 302 mph reading, measured by radar, during the EF5 tornado that struck Moore on May 3, 1999, according to Jeff Masters, meteorology director at the Weather Underground.
Still, when it comes to weather events, scientists usually know more about and can better predict hurricanes, winter storms, heat waves and other big events.
That's because even though a tornado like the one that struck Moore was 1.3 miles wide, with a path of 17 miles long, in meteorological terms it was small, hard to track, rare and even harder to study. So tornadoes are still more of a mystery than their hurricane cousins, even though tropical storms form over ocean areas where no one is, while this tornado formed only miles from the very National Weather Service office that specializes in tornadoes.
"This phenomenon can be so deadly you would think that something that catastrophic, that severe would lend itself to understanding," said Adam Houston, meteorology professor at the University of Nebraska, Lincoln. "But we're fighting the inherent unpredictability of these small-scale phenomena."
Unlike hurricanes, which forecasters can fly through in planes and monitor with buoys and weather stations, usually over a period of days, tornadoes form quickly and normally last only a matter of minutes. While meteorologists and television hosts chase tornadoes and try to get readings, it's not usually enough. This storm lasted 40 minutes — long for a regular tornado but not too unusual for such a violent one, said research meteorologist Harold Brooks at the National Severe Storms Laboratory in Norman, Okla.
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