USA Tornadoes - 2008 already unusually active by Steph Ball
With the start of spring comes the start of the tornado season in the USA and yet 2008 has already seen an unusually high number of tornadoes.
The National Weather Service (NWS) keeps a count of all tornadoes via Local Storm Reports (LSR’s) collated from its various offices across the country. Preliminary reports are often over estimated as offices receive several reports for the same tornado. However despite this, the number of tornadoes reported in the first three months of this year still far exceeds the number in previous years.
From January to March 2008 up to 516 preliminary tornado reports were noted, this compares to 330 in the same period in 2007 and is said to be almost two and a half times the 10-year average. The increased activity has been attributed to the current La Niña and though this is expected to weaken over the spring, the season has only just officially begun.
It is usually during the spring months that tornado activity is at its highest with conditions ripe for their development. A large portion of these tornadoes develop across the central US in an area referred to as “Tornado Alley”.
An outbreak of severe storms is expected to develop across central US later this week which could spawn some significant tornadoes.
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