Oklahoma tornado: Latest killer storm followed almost identical path to 1999 twister

The monster tornado in suburban Oklahoma City loosely followed the path of akiller twister that slammed the region in May 1999.

The National Weather Service estimated that the storm that struck Mooreyesterday had wind speeds of up to 200mph and was at least half a mile wide.The 1999 storm had winds clocked at 300mph, according to the weather servicewebsite, and it destroyed or damaged more than 8,000 homes, killing at leasttwo people.

Kelsey Angle, a weather service meteorologist in Kansas City, Missouri, saidwas unusual for two such powerful tornadoes to track roughly the same path. The1999 twister was part of a two-day outbreak sweeping mostly across centralOklahoma - similar to the past two days.

The weather service has tentatively classified the Moore twister's windspeeds as an EF4 on a five-point scale. Less than 1% of all tornadoes reach EF4or EF5.

The thunderstorm developed in an area where warm moist air rose into coolerair. Winds in the area caused the storm to rotate, and that rotation promotedthe development of a tornado. The most destructive and deadly tornadoes developfrom rotating thunderstorms.


                                     [Oklahoma tornado: Ten more deadly US twisters]

The biggest known tornado was nearly two and a half miles wide at its peakwidth, which the weather service describes as near the maximum size for atornado. It struck Hallam, Nebraska, in May 2004.

The deadliest tornado, which struck on March 18 1925, killed 695 people inIllinois, Missouri and Indiana.

Deaths from twisters have been declining in recent years because of improvedforecasts and increased awareness by people living in tornado-prone areas,especially in smaller and rural communities.