[su_box title=”Tornado Drill Postponed” box_color=”#ff0000″]Due to the potential of strong to severe thunderstorms across portions of Iowa on Wednesday, March 23, 2016, the Iowa Statewide Tornado Drill has been postponed until Thursday, March 24th.[/su_box]

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.

Tornado Watch vs Warning

• Tornado Watch: Be Prepared! Tornadoes are possible in and near the watch area. Review and discuss your emergency plans and check supplies and your safe room. Be ready to act quickly if a warning is issued or you suspect a tornado is approaching. Acting early helps to save lives! Watches are issued by the Storm Prediction Center for counties where tornadoes may occur. The watch area is typically large, covering numerous counties or even states.
• Tornado Warning: Take Action! A tornado has been sighted or indicated by weather radar. There is imminent danger to life and property. Move to an interior room on the lowest floor of a sturdy building. Avoid windows. If in a mobile home, a vehicle, or outdoors, move to the closest substantial shelter and protect yourself from flying debris. Warnings are issued by your local forecast office. Warnings typically encompass a much smaller area (around the size of a city or small county) that may be impacted by a tornado identified by a forecaster on Radar or by a trained spotter/law enforcement who is watching the storm.

EF Scale

The severity of a tornado is expressed through the use of the Enhanced Fujita Scale (“EF Scale”). The EF Scale became operational on February 1, 2007 and is used to assign a ‘rating’ to a tornado based on estimated wind speeds and related damage. It is important to note that the EF Scale is a set of wind estimates, not wind measurements. The estimates are derived based on the damage done by a tornado to homes, crops, trees, etc. An EF SCale rating is determined based on the highest wind speed which occurred within a damage path.

The EF Scale was revised from the original Fujita Scale (“F Scale”) to align wind speeds more closely with associated storm damage. The Fujita Scale is named after Dr. T. Theordore Fujita who first introduced the scale in 1971. The new EF Scale is now used in place of the F scale. The main difference between the F and EF scale is that the EF Scale takes into account the construction of structures damaged by a tornado.

Tornado Safety

Before the Storm:

• Know the county in which you live and the names of nearby cities.
• Have a NOAA Weather Radio with a warning alarm tone and battery backup.
• Make sure your family and people in your workplace are familiar with these safety precautions. Review the procedures and practice them.

In a Home or Building:

• Move underneath a table, workbench, or staircase.
• Stay away from the corners of the room because debris is usually displaced into those areas.
• Mobile homes, even if tied down, offer little protection from tornadoes and should be abandoned.
• If an underground shelter is not available, move to the lowest, most interior room available.
• Stay away from windows.

In an Office Building, Shopping Mall, or School:

• Go into an interior hallway and crouch on the ground floor against a wall.
• Cover your head with your hands.
• Leave wide-open rooms like gyms, auditoriums, or the common areas of shopping malls.

If you are Caught out in the Open or in a Vehicle:

• Never try to outrun a tornado especially if it is nearby. Tornadoes can move at speeds of over 50 MPH and change directions quickly.
• Highway overpasses are not safe shelters for tornadoes and should be avoided.

Many people mistakenly think that highway overpasses provide safety from a tornado. In reality, an overpass may be on of the worst places to seek shelter from a tornado. Seeking shelter under an overpass puts you at a greater risk of being killed or injured by flying debris.

Tornadic winds can make the most benign item a dangerous missile. In addition to the debris that can injure you, the winds under an overpass are channeled and could easily blow you or carry you out from under the overpass.

Information Courtesy: National Weather Service Des Moines, Iowa