Tornado emergency
A Tornado Emergency is enhanced wording of tornado warnings used by the National Weather Service (NWS) in the United States during significant tornado occurrences in highly populated areas. Although not a new warning type from the NWS, instead issued in a Severe Weather Statement (or in rare cases, in the initial Tornado Warning), a Tornado Emergency generally means that significant, widespread damage is expected to continue and a high likelihood of numerous fatalities is expected with a large, strong to violent tornado.[1]
There are instances where very few to no fatalities have resulted from strong to violent tornadoes (rated EF2-EF5 on the Enhanced Fujita Scale), and not all tornadoes of at least ¼-mile in width produce catastrophic damage (though this is often assumed to be the case). Regardless, people in the path of a large tornado must take immediate safety precautions.
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[edit] History
[edit] First use
The term was first used during the May 3, 1999 tornado outbreak that spawned the The Bridge Creek-Moore F5 tornado just south of Oklahoma City. On that day, between 5:30 and 6:30 p.m., David Andra, the Science and Operations Officer at the National Weather Service Norman office watched as a large, destructive tornado approached Oklahoma City. This led to the issuance of the first tornado emergency.[2]
"As the large tornado approached western sections of the OKC metro area, we asked ourselves more than once, 'Are we doing all we can do to provide the best warnings and information?' It became apparent that unique and eye-catching phrases needed to be included in the products. At one point we used the phrase 'Tornado Emergency' to paint the picture that a rare and deadly tornado was imminent in the metro area. We hoped that such dire phrases would prompt action from anyone that still had any questions about what was about to happen.[3]"
[edit] Text of the Moore Tornado Emergency
...TORNADO EMERGENCY IN SOUTH OKLAHOMA CITY METRO AREA... AT 6:57 PM CDT...A LARGE TORNADO WAS MOVING ALONG INTERSTATE 44 WEST OF NEWCASTLE. ON ITS PRESENT PATH...THIS LARGE DAMAGING TORNADO WILL ENTER SOUTHWEST SECTIONS OF THE OKLAHOMA CITY METRO AREA BETWEEN 7:15 AND 7:30 PM. PERSONS IN MOORE AND SOUTH OKLAHOMA CITY SHOULD TAKE IMMEDIATE TORNADO PRECAUTIONS! THIS IS AN EXTREMELY DANGEROUS AND LIFE THREATENING SITUATION. IF YOU ARE IN THE PATH OF THIS LARGE AND DESTRUCTIVE TORNADO...TAKE COVER IMMEDIATELY. DOPPLER RADAR HAS INDICATED THIS STORM MAY CONTAIN DESTRUCTIVE HAIL TO THE SIZE OF BASEBALLS...OR LARGER.
Source:[4]
[edit] Standardization and recent usage
After the original usage for the Moore, OK, tornado in 1999, the term Tornado Emergency was used by other NWS offices, although no uniform criteria existed and the issuance was entirely at the discretion of the forecaster issuing the warnings. Usage of the term varied from simply confirmed tornadoes in populated areas to significant, rare tornadoes causing severe damage and injuries. Some National Weather Service forecast offices, such as the one serving the Des Moines, IA Metropolitan Area, have created standardized criteria and purpose for the usages of the heightened wording. Because data about the tornado and its exact path are often ascertained after the initial tornado warning is issued, this designation is usually added to the Severe Weather Statement (SAME code: SVS) that is used to follow-up a tornado warning.
On April 2, 2012, the NWS began an experimental program within its Wichita, Topeka, Springfield, St. Louis, and Kansas City/Pleasant Hill offices in Kansas and Missouri called Impact Based Warning, which allows the respective offices to enhance warning information, such as adding tags to the warning messages which signify the potential damage severity.[5][6]
[edit] Criteria
National Weather Service Des Moines is one of the forecast offices that has created a set purpose and criteria to the usage of "Tornado Emergency" in Tornado Warning products, which they made effective on March 12, 2010.[1] According to their office, the purpose of the tornado emergency wording is:
- To motivate and provide a sense of urgency to persons in the path of this storm to take immediate shelter in a reinforced structure that offers maximum protection from destructive winds.
- To communicate to state, local, and county officials and emergency responders that they should prepare for immediate search and rescue operations.
- To communicate the need to prepare for immediate medical emergencies, evacuation measures, and emergency sheltering.
And before usage, the following criteria must be met:
- A large and catastrophic tornado has been confirmed and will continue (a radar signature alone is not sufficient).
- The tornado will have a high impact and/or affect a highly vulnerable population (estimated to be once every 10 years for central Iowa).
- The tornado is expected to cause numerous fatalities.
The National Weather Service office in Nashville, TN also created criteria for the usage of tornado emergency effective January 1, 2011. It states, "Tornado Emergency can be inserted in the third bulletin of the initial tornado warning (TOR) or in a severe weather statement (SVS)." Before the phrase can be used:
- a confirmed large tornado must be going through a highly populated area such as Metro Nashville
- a violent tornado with a significant damage history
- a confirmed tornado, radar shows evidence of debris
- the confirmed tornado is expected to cause significant widespread damage and loss of life.
[edit] Tornado safety
It is recommended that people in the path of a large and violent tornado, whether referenced in a Tornado Warning or a Tornado Emergency, seek shelter in a basement, cellar or safe room, as more violent tornadoes pose a significant risk of very serious injury or death for people above ground level. Those who do not have below-ground shelter are still advised to take cover in a room in the center of the home on the lowest floor, and cover themselves with some type of thick padding (mattress, blankets, etc.), to protect against falling debris in the event the roof and ceiling collapse.[7]
[edit] Example of tornado emergency usage
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SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE JACKSON MS 1203 PM CDT SAT APR 24 2010 ...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1230 PM CDT FOR CENTRAL YAZOO COUNTY... ...THIS IS A TORNADO EMERGENCY FOR THE WARNED AREA... AT 1203 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS AND STORM SPOTTERS WERE TRACKING A LARGE AND EXTREMELY DANGEROUS WEDGE TORNADO. THIS TORNADO WAS LOCATED 6 MILES NORTH OF SATARTIA MOVING NORTHEAST AT 60 MPH. THE TORNADO WILL BE NEAR... YAZOO CITY AND LITTLE YAZOO BY 1210 PM CDT... MYRLEVILLE BY 1215 PM CDT... BENTON AND EDEN BY 1220 PM CDT... MIDWAY BY 1225 PM CDT... PRECAUTIONARY/PREPAREDNESS ACTIONS... A TORNADO WARNING MEANS THAT A TORNADO IS OCCURRING OR IMMINENT. YOU SHOULD ACTIVATE YOUR TORNADO ACTION PLAN AND TAKE PROTECTIVE ACTION NOW. SIGNIFICANT DAMAGE HAS OCCURRED WITH THIS SIGNIFICANT TORNADO! THIS IS AN EXTREMELY DANGEROUS AND SERIOUS LIFE THREATENING SITUATION. THIS STORM IS CAPABLE OF PRODUCING STRONG TO VIOLENT TORNADOES. IF YOU ARE IN THE PATH OF THIS TORNADO...TAKE COVER IMMEDIATELY! A TORNADO WATCH REMAINS IN EFFECT UNTIL 800 PM CDT SATURDAY EVENING FOR MISSISSIPPI.
[edit] List of tornado emergencies issued
[edit] See also
[edit] References
- ^ a b "Tornado Emergency Media Advisory". NWS - Des Moines, Iowa. March 12, 2010. http://www.crh.noaa.gov/images/dmx/Media%20Advisory%202010-01.pdf. Retrieved 2010-03-29.
- ^ "TORNADO EMERGENCY IN SOUTH OKLAHOMA CITY METRO AREA". NWS - Norman, Oklahoma. May 3, 1999. http://www.srh.noaa.gov/oun/storms/19990503/svsokc.txt. Retrieved 2007-08-13.[dead link]
- ^ "May 3rd, 1999 from the NWS's Perspective". The Southern Plains Cyclone (National Weather Service) 2 (2). Spring 2004. Archived from the original on 2004-11-08. http://replay.waybackmachine.org/20041108065124/http://www.srh.noaa.gov/oun/newsletter/spring2004/#19990503. Retrieved 2008-02-15.
- ^ Mathis, Nancy (2007). "Inside the Bear's Cage". Storm Warning: The Story of a Killer Tornado. Touchstone. p. 129. ISBN 0743280539.
- ^ "Impact Based Warning Experimental Product". National Weather Service. http://www.crh.noaa.gov/images/crh/IBW/Resources/IBW1pager.pdf. Retrieved 2012-04-04.
- ^ Draper, Bill (2012-04-01). "'UNSURVIVABLE!' New Tornado Warnings Aim to Scare". Associated Press. http://www.google.com/hostednews/ap/article/ALeqM5hN7kL7Os8Z9HMTZdDX_xCk-_9Z6w. Retrieved 2012-04-04.
- ^ http://www.spc.noaa.gov/faq/tornado/#Safety
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