Tornado emergency

Large, violent tornadoes can cause catastrophic damage when striking populated areas.

A tornado emergency is an enhanced version of the tornado warning used by the National Weather Service (NWS) in the United States, during significant tornado occurrences in highly populated areas. Although it is not a new warning type from the NWS, issued instead within 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 occur and a high likelihood of numerous fatalities is expected with a large, strong to violent tornado.^[1] A tornado emergency may also be issued when computer models predict a 100% chance that a powerful tornado will strike a populated area.

Although tornadoes that are classified in damage surveys as "strong" or "violent" (rated EF2-EF5 on the Enhanced Fujita Scale) are capable of significant property damage and loss of life, there have been instances in which these type of tornadoes have resulted in very few to no fatalities; in turn, not all tornadoes of ¼-mile in width or larger 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 if they are in or near the projected path of the storm.

History

First use

The term was first used during the May 3, 1999 tornado outbreak that spawned an F5 tornado which struck the municipalities of Bridge Creek and Moore, located just south of Oklahoma City, followed by southern and eastern parts of the city itself, Del City, and Midwest City. On that day, between 5:30 and 6:30 p.m., David Andra, the Science and Operations Officer at the National Weather Service Weather Forecast Office in Norman watched as the large, destructive tornado approached Oklahoma City. This led to the issuance of the first tornado emergency, which in this instance was released as a standalone weather statement issued separately from the original tornado warning.^[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]"

Text of the South Oklahoma City metro Tornado Emergency from May 3, 1999

...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]^[5]

Evolved usage

At 3:01 p.m. CDT on May 20, 2013, this bulletin was issued by the National Weather Service Norman forecast office confirming that a destructive tornado was on the ground and headed for Moore and southern portions of Oklahoma City, Oklahoma. Note the differences between this bulletin and the first-ever bulletin from 1999. It should also be noted that this was issued during an updated tornado warning and not in a follow-up severe weather statement.

Text of the Moore Tornado Emergency from May 20, 2013

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE NORMAN OK
301 PM CDT MON MAY 20 2013

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHWESTERN MCCLAIN COUNTY IN CENTRAL OKLAHOMA...
  SOUTHERN OKLAHOMA COUNTY IN CENTRAL OKLAHOMA...
  NORTHERN CLEVELAND COUNTY IN CENTRAL OKLAHOMA...

* UNTIL 345 PM CDT

* AT 259 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS AND STORM
  SPOTTERS WERE TRACKING A LARGE AND EXTREMELY DANGEROUS TORNADO NEAR
  NEWCASTLE. DOPPLER RADAR SHOWED THIS TORNADO MOVING NORTHEAST AT 20
  MPH.

THIS IS A TORNADO EMERGENCY FOR MOORE AND SOUTH OKLAHOMA CITY.

IN ADDITION TO A TORNADO...LARGE DESTRUCTIVE HAIL UP TO TENNIS BALL
SIZE IS EXPECTED WITH THIS STORM.

* LOCATIONS IMPACTED INCLUDE...
  MIDWEST CITY...MOORE...NEWCASTLE...STANLEY DRAPER LAKE...TINKER AIR
  FORCE BASE AND VALLEY BROOK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS AN EXTREMELY DANGEROUS AND LIFE THREATENING SITUATION. IF YOU
CANNOT GET UNDERGROUND GO TO A STORM SHELTER OR AN INTERIOR ROOM OF A
STURDY BUILDING NOW.

TAKE COVER NOW IN A STORM SHELTER OR AN INTERIOR ROOM OF A STURDY
BUILDING. STAY AWAY FROM DOORS AND WINDOWS.
&&

$$

Source:^[6]

Standardization and recent usage

After the original usage for the May 3, 1999 F5 tornado, the term Tornado Emergency was used by other National Weather Service Weather Forecast Offices (WFOs), 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 NWS forecast offices, such as the one serving the Des Moines, Iowa 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 National Weather Service 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. In regards to tornadoes, the creation of this multi-tiered system resulted in the implementation of an intermediate tornado warning product, a Particularly Dangerous Situation Tornado Warning.^[7]^[8]

On April 1, 2013, the IBW experiment expanded to include all National Weather Service WFOs within the Central Region;^[9] the IBW experiment was expanded again to include eight additional offices within the Eastern, Southern and Western Regions in the spring of 2014.^[10] Within the span of eleven days, the National Weather Service WFO in Norman issued tornado emergencies for parts of the Oklahoma City metropolitan area and central Oklahoma: first on May 20, 2013 for the EF5 tornado that struck Moore and portions of southern Oklahoma City,^[11] and again on May 31, for portions of eastern Canadian County and western sections of the immediate Oklahoma City area for another tornado.

The usage of tornado emergencies to alert major population centers to the imminent threat of a catastrophic tornado impact has also led to the development of the flash flood emergency which is similarly employed when severe flash floods threaten populated areas.

Criteria

The National Weather Service Weather Forecast Office in Des Moines is one of the forecast offices to have created a set purpose and criteria for the usage of "tornado emergencies" in tornado warning products, which were made effective on March 12, 2010.^[1] According to the Des Moines office, the purpose of the tornado emergency wording is as follows:

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, Tennessee also created criteria to declare a tornado emergency within a tornado warning statement 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.

Tornado safety

Main article: Tornado preparedness

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 stronger tornadoes (particularly those significant enough to warrant the inclusion of a tornado emergency declaration within a tornado warning) pose a significant risk of major 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 (such as mattresses or blankets), to protect against falling debris in the event that the roof and ceiling collapse.^[12]

Example of tornado emergency usage

	Tornado Emergency Alabama An example of a tornado emergency issued in Alabama
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SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MEMPHIS TN
417 PM CST WED DEC 23 2015

...TORNADO EMERGENCY FOR HOLLY SPRINGS...

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 445 PM CST FOR
NORTHWESTERN LAFAYETTE...MARSHALL...SOUTHEASTERN TATE AND
NORTHEASTERN PANOLA COUNTIES...
        
AT 416 PM CST...A CONFIRMED LARGE AND DESTRUCTIVE TORNADO WAS LOCATED
NEAR MARIANNA...OR 8 MILES WEST OF WALL DOXEY STATE PARK...MOVING
NORTHEAST AT 55 MPH.

TORNADO EMERGENCY FOR HOLLY SPRINGS. TAKE COVER NOW. THIS IS A
PARTICULARLY DANGEROUS SITUATION.

HAZARD...DEADLY TORNADO. 

SOURCE...RADAR CONFIRMED TORNADO. 

IMPACT...YOU ARE IN A LIFE THREATENING SITUATION. FLYING DEBRIS MAY 
         BE DEADLY TO THOSE CAUGHT WITHOUT SHELTER. MOBILE HOMES 
         WILL BE DESTROYED. CONSIDERABLE DAMAGE TO 
         HOMES...BUSINESSES AND VEHICLES IS LIKELY AND COMPLETE 
         DESTRUCTION IS POSSIBLE. 

THE TORNADO WILL BE NEAR...
  MARIANNA AROUND 420 PM CST.
  WALL DOXEY STATE PARK AROUND 425 PM CST.
  HOLLY SPRINGS AROUND 430 PM CST.

OTHER LOCATIONS IMPACTED BY THIS TORNADIC THUNDERSTORM INCLUDE
MAHON...LOOXAHOMA...GLENVILLE...ROCKHILL...POTTS CAMP...BLACKWATER...
WAITES...MC GHEE...LAKE CENTER AND AIKEN.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPEAT...A LARGE...EXTREMELY DANGEROUS...AND POTENTIALLY DEADLY
TORNADO IS ON THE GROUND. TO PROTECT YOUR LIFE...TAKE COVER NOW. 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.

A LARGE AND EXTREMELY DANGEROUS TORNADO IS ON THE GROUND. TAKE
IMMEDIATE TORNADO PRECAUTIONS. THIS IS AN EMERGENCY SITUATION.

References

1 2 "Tornado Emergency Media Advisory" (PDF). NWS - Des Moines, Iowa. March 12, 2010. Retrieved 2010-03-29.
↑ "Tornado emergency in south oklahoma city metro area". NWS - Norman, Oklahoma. May 3, 1999. Archived from the original on February 13, 2008. Retrieved 2007-08-13.
↑ "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. Retrieved 2008-02-15.
↑ Mathis, Nancy (2007). "Inside the Bear's Cage". Storm Warning: The Story of a Killer Tornado. Touchstone. p. 129. ISBN 0-7432-8053-9.
↑ "What is a Tornado Emergency?". Weather Forecast Office. Little Rock, Arkansas: National Oceanic and Atmospheric Administration. February 11, 2015. Missing or empty |url= (help); |access-date= requires |url= (help)
↑ National Weather Service, Norman Weather Forecast Office (2013-05-20). "Tornado Warning". Iowa State University Department of Agronomy. Retrieved 2013-05-24.
↑ "Impact Based Warning Experimental Product" (PDF). National Weather Service. Retrieved 2012-04-04.
↑ Draper, Bill (2012-04-01). "'UNSURVIVABLE!' New Tornado Warnings Aim to Scare". Yahoo! News and the Associated Press. Retrieved 2012-04-04.
↑ "Impact Based Warning Experimental Product". Crh.noaa.gov. Retrieved 2014-01-22.
↑ National Weather Service (2014). "Impact Based Warnings". National Oceanic and Atmospheric Administration. Retrieved March 12, 2014.
↑ Howell, George (2013-05-21). "Okla. Medical Examiner preparing for '40 more bodies' | National News - KCCI Home". Kcci.com. Retrieved 2014-01-22.
↑ "The Online Tornado FAQ (by Roger Edwards, SPC)". Spc.noaa.gov. Retrieved 2014-01-22.

Severe weather terminology in the United States

Severe
storms

Thunderstorm	Advisory Watch PDS Watch Warning

Tornado	Watch PDS Watch Warning PDS Warning Emergency

Marine Thunderstorm	Special marine warning

Winter
weather

Advisories	Winter Weather Advisory

Winter storm	Watch Warning

Blizzard/Blowing Snow	Blowing Snow advisory Blizzard watch Blizzard warning

Heavy snow	Warning

Lake-effect snow	Advisory Watch Warning

Ice	Freezing rain advisory Ice storm warning

Tropical
Cyclones

Tropical storms	Watch Warning

Hurricanes	Watch Warning

Inland Advisories	Inland Tropical Storm Watch Inland Tropical Storm Warning Inland Hurricane Watch Inland Hurricane Warning

Hurricane Local Statement

Flood

Flood	Watch Warning

Flash flood	Watch PDS Watch Warning Emergency

Coastal flood	Advisory Watch Warning

Lakeshore flood	Advisory Watch Warning Seiche Warning

River flood	Advisory Watch Warning

Urban and small stream flood	Advisory

Apparent
temperature

Heat index	Heat advisory Excessive heat watch Excessive heat warning

Wind chill	Advisory Watch Warning PDS Warning

Extreme cold	Watch Warning

Freeze	Watch Warning Hard Freeze Warning Frost Advisory

Maritime
and
coastal
weather

Marine Winds	Small craft advisory Brisk wind advisory Lake Wind Advisory

Gale	Watch Warning

Storm	Watch Warning

Hurricane Force Wind	Watch Warning

Hazardous Seas	Watch Warning

Freezing Spray	Freezing spray advisory Heavy freezing spray watch Heavy freezing spray warning

High Surf	Advisory Warning

Wind

Advisory-Force Winds	Wind Advisory

Gale-Force Winds	High wind watch High wind warning

Major Hurricane-Force Winds	Extreme wind warning

Airborne
particulates

Dust/sand	Blowing Dust Advisory Dust Storm Warning

Fog/Smoke	Dense Fog Advisory Dense Smoke Advisory

Ash	Ashfall Advisory

Air pollution	Air Stagnation Advisory

Fire

Aviation

Center Weather Advisory
SIGMET
Volcanic Ash Advisory

Weather scales
used by NWS

Beaufort (wind)
Enhanced Fujita (tornadoes)
Saffir-Simpson Hurricane Scale (tropical cyclones)

Other

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