By Jim Hagerty
It’s been more than a week since a tornado touched down in Caledonia, Ill., damaging several buildings and overturning a school bus. Those affected by the Monday, Nov. 22, twister are slowly putting their lives back together. Meantime, experts at the National Weather Service continue to track inclement weather so people know when to take shelter from potentially deadly conditions.
According to Chief Meteorologist Ed Fenelon, last week’s touchdown followed a series of warnings and watches, all meant to alert those in the area to take cover. Fenelon, who runs the National Weather Service office in Chicago, said about 70 percent of tornadoes are preceded by a warning or a watch. This means meteorologists stay busy tracking the storms as they develop. As the Rockford area learned last week, a series of National Weather Center alerts played a significant role in preventing serious injuries during the Boone County tornado.
Commonly uttered by weather reporters, the terms, “watch” and “warning” are different. Fenelon said knowing the difference is vital, especially when alerts are changing.
“A watch,” Fenelon said, “means that current weather conditions are favorable for a tornado to develop. A warning means that a tornado has been spotted or is imminent.”
Last Monday, Nov. 22, a tornado watch was issued at 11:16 a.m. and was to expire at 6 p.m. This gave residents time to take cover from the imminent twister. As weather trackers followed conditions, the National Weather Service issued a warning at 3:03 p.m., shortly before the tornado ripped through the town of Caledonia. The watch, issued for Boone and McHenry counties, was lifted at 3:56 p.m.
For the National Weather Service, having both warnings and watches as part of its alert system allows everyone to stay proactive, especially because weather can change without notice.
“As much as we’d like it to be, meteorology is far from an exact science,” Fenelon said. “That’s why it’s important for everyone to take precautions against mother nature.”
Crews worked well into Tuesday, Nov. 23, restoring power to about 40,000 ComEd customers, while Caledonia was closed to everyone but residents during cleanup from the storm.
From the Dec. 1-7, 2010 issue