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Moore Tornado an EF-5; $2 Billion Damage Estimate: 3rd Costliest Tornado in History

By: Dr. Jeff Masters, 3:22 PM GMT on May 22, 2013

The Moore, Oklahoma tornado of May 20, 2013 is now ranked an EF-5, making it one of only 59 U.S. tornadoes to achieve that distinction since record keeping began in 1950. The National Weather Service in Norman, Oklahoma announced Tuesday that their damage survey teams found an area of EF-5 damage near Briarwood Elementary School, with winds of 200 - 210 mph indicated. There were no EF-5 tornadoes observed in 2012, and the last time the U.S. had an EF-5 was on May 24, 2011, when the Oklahoma towns of Calumet, El Reno, Piedmont, and Guthrie were hit by an EF-5 with 210+ mph winds that killed nine people. The maximum width of the 2013 Moore tornado's damage swath was a huge 1.3 miles. Detailed damage survey information in Google Earth Format provided by the Norman, OK NWS office shows that the typical width of the EF-0 and greater damage swath was about 0.6 miles, and the EF-4 damage area was about 0.1 miles across at its widest. EF-4 damage occurred along approximately 4 miles of the tornado's 17-mile long path. The damage swath from the May 20, 2013 tornado as it cut through the most densely built up portions of Moore was roughly 1.5 times as wide as the one from the May 3, 1999 EF-5 tornado. That tornado was the 4th costliest in history ($1.4 billion 2011 dollars), so it is a good bet that the 2013 Moore tornado will end up being even more expensive. This morning, the Oklahoma Insurance Department said the preliminary tornado damage estimate could top $2 billion. This would make the 2013 Moore tornado the 2nd most expensive tornado in history (as ranked by NOAA/SPC) or 3rd most expensive (as ranked by insurance broker Aon Benfield.) The nine billion-dollar tornadoes (2013 dollars) are:

1) Joplin, Missouri, May 22, 2011, $2.9 billion
2) Tuscaloosa, Alabama, April 27, 2011, $2.3 billion (not in SPC's list)
3) Moore, Oklahoma, May 20, 2013, $2 billion
4) Topeka, Kansas, June 8, 1966, $1.8 billion
5) Lubbock, Texas, May 11, 1970, $1.5 billion
6) Bridge Creek-Moore, Oklahoma, May 3, 1999, $1.4 billion
7) Hackleburg, Alabama, April 27, 2011, $1.3 billion (not in SPC's list)
8) Xenia, Ohio, April 3, 1974, $1.1 billion
9) Omaha, Nebraska, May 6, 1975, $1 billion

Figure 1. The Moore, Oklahoma tornado of May 20, 2013 (AP Photo/Alonzo Adams)

Figure 2. The damage swath of the Moore, Oklahoma tornado of May 20, 2013. EF-4 damage (red colors) occurred along roughly 4 miles of the 17-mile path, and the EF-4 damage swath was up to 0.1 miles wide. The tornado's maximum width of 1.3 miles (EF-0 and greater damage) occurred over a relatively small portion of the path, before the storm reached Moore. Image credit: NWS Norman.

Figure 3. On May 20, 2013, a supercell thunderstorm in central Oklahoma spawned a destructive tornado that passed just south of Oklahoma City. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this natural-color image of the storm system at 2:40 p.m. Central Daylight Time (19:40 Universal Time), just minutes before the devastating twister began. The red line on the image depicts the tornado’s track. Image credit: NASA Earth Observatory.

There have been bigger tornadoes
The 1.3 mile maximum width of the 2013 Moore tornado's damage swath was not a record. Wikipedia documents that the EF-3 Edmonson, Texas tornado of May 31, 1968 had a damage path width between 2 and 3 miles (3.2 and 4.8 km) wide. The EF-4 Wilber - Hallam, Nebraska tornado on May 22, 2004 was of similar size, with a damage path up to 2.5 miles wide. Doppler radar measurements indicate that the May 4, 1999 Mulhall, Oklahoma EF-4 tornado--which thankfully passed mostly over farmland--would have caused damage over a path 4 miles wide at its peak size, had it encountered a built-up area. The EF-5 tornado that devastated Greensburg, Kansas on May 4, 2007 was 1.7 miles wide.

Figure 4. Damage swath of the Wilber - Hallam, Nebraska EF-4 tornado of May 22, 2004 was up to 2.5 miles wide, making it one of the largest tornadoes on record.

Figure 5. Severe weather outlook for Wednesday, May 22, calls for a "Slight Risk" of severe weather over portions of the Ohio Valley and Northeast U.S. You can follow today's severe weather from our Severe Weather page.

No tornadoes reported on Tuesday; "Slight Risk" of severe weather on Wednesday
The severe weather outbreak of May 18 - 22 peaked on Sunday and Monday. We did not record any tornadoes on Tuesday, though there were many reports of large hail and damaging winds, including three thunderstorms with wind gusts over 74 mph. Tuesday was the first day since May 14 that no tornadoes were recorded in the U.S. And after issuing four consecutive "Moderate Risk" outlooks for severe weather, NOAA's Storm Prediction Center (SPC) is going with only a "Slight Risk" for severe weather on Wednesday in the U.S., with the main severe weather action expected to affect portions of the Ohio Valley and Northeast U.S. The primary threat will be straight-line wind damage and large hail, though we can't rule out a few tornadoes. During the three-day period May 18 - May 20, 70 tornadoes (preliminary) were recorded by SPC.

Video 1. Charles Cook caught the birth of the May 20, 2013 tornado at Newcastle, OK. It moved from there to Moore where it caused catastrophic devastation.

Video 2. NOAA's GOES-East satellite collected this view of the storm system that spawned a deadly tornado over Moore, Oklahoma on May 20, 2013. The animation runs from 10:45 a.m. through 6:45 p.m., Central Daylight Time. Images courtesy NASA GOES Project Science: ‪http://goes.gsfc.nasa.gov/‬

The Norman, OK NWS office has an excellent page with detailed info on the Moore tornado.

I did a 10-minute Skype interview with democracynow.org on Tuesday morning, discussing the Moore tornado.

I greatly appreciate all the valuable links members of the WU community have posted here, and I have used many of them in my posts over the past day. Keep up the great work!

How to help
Portlight Strategies, an organization that supports disaster victims with disabilities, will be working with shelter operators and disability stakeholder organizations in Oklahoma to serve the needs of people with disabilities. Further information and how to offer additional support can be found on their website.

Donations can be made to American Red Cross disaster relief at redcross.org/weather or by texting WEATHER to 90999 to donate $10.

Donations can be made on The Salvation Army's website or by texting STORM to 80888 to donate $10. You can also call to make donations of other monetary amounts at (800) 725-2769.

Jeff Masters


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.