Sheldon, Iowa — This is Severe Weather Awareness Week in Iowa. Today’s theme is tornadoes. Normally on the Wednesday of Severe Weather Awareness Week, a statewide tornado drill is scheduled.
However, due to impending weather, and especially the threat of actual severe weather in southeast Iowa, the tornado drill has been postponed a day, and will be tomorrow instead. You can expect outdoor warning sirens to sound in several communities in the 10 AM hour tomorrow.
National Weather Service Warning Coordination Meteorologist Todd Heitkamp from the Sioux Falls office says that for better or worse, tornadoes seem to be the most “popular” severe weather topic.
The weather service says a tornado is a rapidly rotating column of air in contact with the ground. A visible cloud is not needed for a tornado to be in progress. Some tornadoes may not appear to extend to the ground but are causing considerable damage. Tornadoes take on various shapes and sizes, and most produce winds less than 120 mph. However, a few are capable of producing winds over 200 mph. Some tornadoes are very small and last for only a minute or so, while others can be a mile wide or larger and stay on the ground for over an hour.
In addition to the tornado watch which means conditions are right, stay alert — and the tornado warning which means take cover now — the weather service is now issuing a product called a “Tornado Emergency” It is not a new warning, but is used to highlight a confirmed tornado which is expected to be strong and violent. A Tornado Emergency means that significant, widespread damage with a high likelihood of numerous fatalities is expected to continue.
Weather Service experts advise that when you are taking cover from a tornado, to remember the acronym “DUCK”: D for “Down to the lowest level like a basement or interior room on the first floor; U for Get Under something sturdy; C for Cover your head; and K for Keep in your shelter until the storm has passed. However, emergency management experts also remind us that an “all clear” siren is not normally sounded anymore.