Weather: An active year for tornadoes, 2011 season baffles experts
Tuscaloosa, Joplin, Minneapolis, and now Springfield, Mass., adds its name to the list. Through May 30 there have been 1,396 tornadoes reported in the United States, according to the Storm Prediction Center in Norman, Okla.
Five hundred eighteen deaths have resulted from these storms. This compares to only 491 tornadoes and 45 deaths reported in the same time period in 2010. The total includes a tornado reported in Park Rapids Monday evening. Though no injuries were reported, damage was widespread across the western part of town and several houses were destroyed. The storm had abated somewhat as it moved into the Bemidji area. Tornado sirens were sounded to alert residents to the approaching storm and the potential for damaging winds.
Why is this year so much worse? Some experts blame the exit of La Nina conditions several months ago. Simply put, La Nina is a system of trade winds that cool the waters of the equatorial region of the Pacific Ocean. The cooling causes the jet stream to move farther north. The jet stream essentially "steers" storm systems across the U.S. Since the jet stream is farther south than normal, the result has been cold northern air mixing with warm southern air resulting in violent weather across much of the Midwest and eastern U.S. The unfortunate reality is no one can say for sure why tornado season has been so active this year.
The prudent course of action when you hear tornado sirens is to seek shelter immediately. Know where you should go when conditions warrant. The lowest level of your home under a stairway or sturdy piece of furniture away from exterior windows is the safest place to be during severe weather. Severe weather after dark can be especially threatening - lightning flashes illuminate the sky only briefly making it difficult to determine whether a tornado is approaching.
Tom Siemers is the Pioneer's circulation manager. Email him at firstname.lastname@example.org