Tornadogefahr im Spät-Winter / Frühling (USA)

[Severestorms]

Hier ein interessanter Artikel über die Tornadogefahr im Spät-Winter / Frühling in den USA:

Late-Winter, Early-Spring Tornadoes Can Be Deadly
February 23, 2008
By WeatherBug Meteorologist, Julie Gaddy

With winter weather still fresh in the minds of the nation, it is understandable to overlook the threat that early-spring tornadoes pose. Across the Southeast, it is vitally important to be aware that February to April is the peak season for tornadoes.


The jet stream is quite strong during the transition from winter to spring, and is usually draped across the southern part of the country. Cold and dry air masses that originate from Canada collide with warm, moist air provided by the Gulf of Mexico. As a result, highly dynamic weather systems form over the Southeast U.S.


During early to mid February, tornadoes are most likely to strike in Florida, Alabama, Mississippi, Louisiana and Texas. Some of these tornadoes form over the waters of the Gulf (called waterspouts) and move ashore. By the middle part of March, the tornado threat spreads north and east into the Ohio River Valley and the Southern Plains. Towards the end of April, the highest threat for tornadoes shifts west into Oklahoma, Arkansas and north Texas.


Although tornadoes that occur in February tend to be weaker than those that occur during April, they can be just as deadly. One factor is that early-season tornadoes occur at any hour of the day, including at night. This can make them hard to see.


Often, the rotation of a tornado will go undetected by Doppler radar because it is too weak or embedded in a broad area of heavy thunderstorms. The storms of early spring also move more quickly thanks to the influence of the strong jet stream. This means that tornadoes could occur with little or no warning.


The biggest outbreak of tornadoes in the U.S. on record occurred April 3-4, 1974. A total of 147 tornadoes were confirmed in the following states: Alabama, Georgia, Illinois, Indiana, Kentucky, Michigan, Mississippi, North Carolina, Ohio, South Carolina, Tennessee, Virginia, and West Virginia.


On March 27, 1994, a total of 26 tornadoes struck Alabama, Georgia, South Carolina and North Carolina, killing 42 people. This tornado outbreak is the most recent of several historical tornado events that have occurred on Palm Sunday.


Since 1997, nearly 680 people have died during the months of February, March and April as a result of a tornado. Of those, nearly half were in a mobile home at the time. Whether you live in a mobile home or not, you should stay informed if severe weather threatens, and have a plan of escape ready beforehand so that you can protect you and your family.

Quelle:
http://weather.weatherbug.com/weather-n ... story=5113

Gruss Chrigi