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Tornado Season is Fast Approaching, Will Peak Mid-Summer

So far this year severe weather has been relatively mild across this United States. Cold air across the central United States has kept the warm moist air at bay, limiting the formation of the violent thunderstorms that can produce a tornado. Since December, NOAA’s Storm Prediction Center has recorded 75% fewer severe weather events, making it the calmest period in 14 years. Thankfully, the few severe storms that have managed to develop haven’t spun off the outbreak of tornadoes that were experienced last year. Comparably, by this time last year over 200 tornadoes had been reported. As we move into the spring and summer months, however, conditions historically become more volatile. Like Hurricanes and Wildfires, Tornadoes have a peak season too.

Tornado probability timeline

A Timeline depicting the daily probably of a Tornado in the United States (Source: NOAA)

Where is Tornado Alley?

As we move out of winter, warm moist air from the Gulf of Mexico begins to creep up the infamous “tornado alley”. Tornado Alley is the swath of the country’s midsection from Northern Texas to the Canadian border. There are no official boundaries for tornado alley and the term itself is more of a media buzz word rather than scientific distinction.  The term, however, isn’t unwarranted. Almost a quarter of all tornadoes occur in this area (depicted in the map below). Although tornadoes can happen across the US, the tornadoes that form in tornado alley are frequently the largest and most destructive.

Large Tornadoes map

Map showing the where in the United States the most EF3-EF5 tornadoes are recorded. (Image from Federal Emergency Management Agency)

The Enhanced Fujita Scale for Measuring Tornadoes

Like Hurricanes, tornadoes are measured by their wind speeds. Also like hurricanes, they are measured from 0-5, but their categories are based on the Enhanced Fujita Scale. The smallest tornadoes swirl between 65-85 mph which can cause localized damage. On the other end of the scale, the largest tornadoes can tear through counties and cause widespread devastation from their 200+ mph winds. The highest recorded wind speed on earth was measured at 302 mph in 1999 by a mobile weather station during an EF5 event near Oklahoma City, OK.  RedZone has found that over the last few years, NOAA has actually developed a way to show tornado paths and destruction. Now anyone can track near-real-time damage from major severe weather events using NOAA’s Damage Viewer.

EF Fujita Scale

The National Oceanic and Atmospheric Association estimates tornado wind speeds by examining damage to property. The Enhanced Fujita scale ensures that all tornados are rated evenly. Tornados with higher wind speeds and increased damage receive higher EF-values. (U.S. Air Force graphic/Senior Airman Thomas Trower)


new orleans tornado

Powerful Tornado Cuts a Path Across East New Orleans

Damage assessment teams are still sifting through destruction left in the wake of a tornado that struck east New Orleans on Tuesday. The tornado’s devastating winds swept through the 9th Ward community, damaging hundreds of homes and businesses.

Residents of the 9th Ward of New Orleans are no strangers to severe storms, having suffered the brunt of Hurricane Katrina in 2005 and extensive flooding last year.  Luckily, out of the nearly 3 dozen injuries reported, only 5 were listed as serious and all but 2 of those injured individuals had been released from the hospital as of February 10.

Louisiana Governor John Bel Edwards declared a state of emergency and has allocated all available resources to begin the daunting process of rebuilding the area.

Interactive map details the tornadoes path. Select damage points for more information. (NOAA/NWS)

An Unprecedented Storm

A survey crew with the National Weather Service determined that the tornado rated as an EF3, reaching wind speeds of up to 165 mph winds and cutting a 10 mile-long path.  Officials at the National Weather Service said that no other EF3 tornado has been recorded in New Orleans in recorded history.

How Are Tornadoes Rated?

Tornadoes were formally rated on the Fujita Scale, named for T. Theodore Fujita who was a University of Chicago meteorologist. He invented the scale in 1971 to assess the wind speed and type of da­mage caused by a tornado.

In February 2007, the Fujita Scale was replaced by the Enhanced Fujita Scale.  It’s similar to the original scale, but it uses a greater number of criteria to determine the level of damage caused.  The “EF” scale classifies severity based on the type of objects damaged.  Small barns for example would have a low score, while the score for thick trees and brick buildings would be relatively high.  The specific damage experienced by a structure is also taken into account (i.e. broken windows, collapsed roof, total destruction, etc).

The Enhanced Fujita Scale classifies tornadoes into six different categories (EF0 through EF5).

New Orleans Tornado Facts:

  • On Tuesday, February 7th 2017, a devastating tornado ripped through east New Orleans
  • The tornado was rated an EF3 with winds speeds reaching 136 to 165 miles per hour.
  • 33 injuries were reported, but fortunately there were no fatalities.
  • The tornado cut a path over 10 miles long and 600 yards wide.
  • The latest count lists 250 structures as a complete loss, 400 with moderate but repairable damage, and another 1,000 structures receiving only minor damage.
  • During the storm some 10,000 homes in the metro area were without power. As of February 9th, crews had restored electricity to 60% of these residents.
  • Winters storms strong enough to produce tornadoes are very rare but last February the area saw a similar outbreak.

Series of Tornadoes Ravage Gulf States

Outbreak of Tornadoes

In the early morning hours of January 21st, a band of severe weather moved into the Gulf of Mexico region, producing a number of deadly tornadoes.  More than 20 funnel touchdowns were reported in total. The worst tornado of the day hit near Purvis, Mississippi, and was rated EF3 on the Enhanced Fujita Scale which rates tornado intensity.  The funnel itself was nearly 900 yards wide, and the storm cut a path length of over 30 miles.  Sadly, four people died in this storm, and the number of homes and businesses that were damaged is still being assessed.

The following day (Jan 22), the Storm Prediction Center issued a High-Risk Severe Weather Event for the entire Gulf Coast region, the first such warning since 2014. In the subsequent 24-hour period, eight more tornadoes touched down.  The worst of the storm system decimated twenty homes with a tornado (estimated > EF2) impacting a trailer park near Adel, Georgia. Survivors described the early morning chaos as “horrific”, with trailers apparently being tossed like rag dolls by the twister.  To date, 15 people are confirmed to have died within Southern Georgia over the weekend.

By January 23rd, the storms weakened, though two more tornadoes were reported in Florida. Fortunately, there were no injuries reported and only minor damage to a pier and a mobile home park was confirmed.

Government Assistance to Affected Areas

A state of emergency was declared in Mississippi and Georgia in the aftermath of the weekend’s severe weather. FEMA has deployed to Alabama, Florida, Georgia, and Mississippi.  The Red Cross also deployed to Georgia on January 22nd to assist in relief efforts. Freshly sworn-in President Trump has promised relief assistance to the affected areas and also offered “our sincere condolences for the lives taken”.

Weekend Severe Weather Facts

  • Timeline: January 21-23
  • Locations: Texas, Alabama, Mississippi, Louisiana, Georgia, South Carolina, and Florida
  • Number of Tornadoes: 34+
  • Highest Reported Winds: 145 mph
  • Casualties: 20+
  • Damages: Estimated $200 Million
  • News Article: WunderBlog


NOAA, Wunderground, Storm Prediction Center