Recent Tornadoes Underscore Our Area's Vulnerability to Such Storms

The area's recent brush with tornadoes provides an important reminder of the need for all of us to pay attention to the weather, to have a way to receive weather warnings, and to have a pre-determined shelter to get to quickly.

NOAA Weather Radio is your best defense against knowing when threatening weather is approaching your location.  It doesn't need to have the broadcast volume turned on to alert you, by simply having it in your home or workplace in monitoring mode; you can be alerted to hazardous weather much like a smoke detector alerts you to a possible fire.  The tornado that developed over Chesterton spun up extremely quickly, and also developed behind an area of stratiform rain, a location where tornadoes do not typically occur.  We heard from at least one resident who stopped in her tracks when heading out to the local library upon hearing her weather radio going off.  Instead of heading outside, she got to her basement just before the tornado hit.  

Tornados are not rare to Chicagoland.  In fact, we live in a very dangerous part of the world when it comes to tornadoes.  There have been 94 significant tornadoes (significant being defined as F2/EF2 or greater in intensity, or any tornado that caused fatalities or injured at least 10 people) in the 8 county Chicago metro area since 1855.  The EF2 tornado in Chesterton is the 94th, and the EF2 tornado in Griffith, Indiana on August 4 of last year was the 93rd.  On average, since 1950, a tornado rated F2/EF2 or higher strikes our area every 1.3 years. 

Tornadoes are rated on a scale of 0 to 5 using the Enhanced Fujita (EF) Scale.  The original Fujita scale was determined by conducting ground and air surveys of the damage path. The F scale was developed in the 1970s and was replaced by a new Enhanced F scale in February, 2007.   EF0=65 to 85 mph, EF1=86-110 mph, EF2=111-135 mph, EF3=136-165 mph, EF4=166-200 mph, EF5=>200 mph.  The EF Scale is used to assign a tornado a 'rating' based on estimated wind speeds and related damage. When tornado-related damage is surveyed, it is compared to a list of Damage Indicators (DIs) and Degrees of Damage (DoD) which help estimate better the range of wind speeds the tornado likely produced. From that, a rating (from EF0 to EF5) is assigned.  For more information on the EF scale, please see www.spc.noaa.gov/faq/tornado/ef-scale.html

Looking again at Chicagoland tornado statistics, a tornado rated F4/EF4 or higher strikes our area once every 9.8 years on average.  The last tornado this powerful in our area struck Plainfield in August of 1990.  Given it’s been 19 years since the last tornado of this magnitude; the area is due, and arguably overdue for a major violent tornado.

What does this mean for you?

If you really want to be on top of all storm warnings, you need to have a NOAA Weather Radio.  It is the closest thing you'll ever have to someone knocking on your door to tell you a tornado is coming.  Once alerted by NOAA Weather Radio, you can tune to television, radio, or the internet for additional details if time permits.

In order to best protect yourself and your loved ones from dangerous weather, you have to pay attention to the weather and be ready to move to shelter when skies darken or a warning is issued.  This means checking the weather forecast frequently, even every hour or more on days when thunderstorms are forecast.  This also means making yourself available to receive a weather warning the instant it is issued.  This is best achieved by having a NOAA Weather Radio in your home, workplace, school, and any place people go.  

When a warning is issued, you'll only have a few minutes to act.  That means a plan must already be in place in your home, workplace, or school that outlines what you will do when severe weather strikes.  Storm shelters must be identified, a method to receive weather warnings identified and operating, and someone must be paying attention to the weather and ready to alert others to move to shelter.

And remember, a watch means conditions are favorable for severe weather to develop.  That is the time to pay attention. A warning means severe weather is occurring or imminent.  That is the time to move to shelter.

The National Weather Service developed the StormReady program to support communities and any entities (your workplace, school, event venue, any public gathering place) in establishing the best defense against hazardous weather. 

For more information, please visit http://www.stormready.noaa.gov/ or http://www.crh.noaa.gov/lot/?n=stormreadysupporter

For more statistics on Chicagoland tornadoes, please see http://www.crh.noaa.gov/lot/?n=SigChiTorn

Edward Fenelon, Chief Meteorologist

National Weather Service, Chicago/Romeoville, IL

edward.fenelon@noaa.gov

 



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