13 years ago, today was the peak of one of the largest and deadliest outbreaks of tornadoes ever to hit the United States.
Over a four-day period from April 25 - April 28, 2011, more than 360 tornadoes touched down from Texas to New York.
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Many of these tornadoes would become very powerful, with four attaining EF5 ratings, 12 becoming EF4′s, and 21 EF3′s.
Over 175 of those tornadoes would touch down in Tennessee, Mississippi, and Alabama, which were the most affected states. These tornadoes caused untold levels of destruction.
319 people lost their lives in the tornadoes and over 3,000 were injured.
In total, the outbreak caused over $12 billion in damages, becoming one of the costliest meteorological disasters on record.
While the outbreak occurred over a four-day period, April 27 was the peak and deadliest day of the outbreak.
In remembrance of 13 years since the day, I have decided to take a look back at some of the ingredients that made this day so deadly and also take a look at some of the notable tornadoes of April 27.
The ingredients:
The morning of April 27 did not start out quiet for much of the Deep South. Thanks to extensive archiving from National Weather Service offices across the south, we have access to a treasure trove of data regarding to setup of the event. The image above shows surface analysis of the atmosphere the morning of April 27, 2011.
A strong cold front with several areas of embedded low-pressure systems was across the Texas Hill Country that morning, draped northeastward into the Arklatex and the Ozarks and then into the lower Ohio Valley. Strong southerly flow ahead of the front allowed for warm, moist air to be in place across Mississippi, Tennessee, and Alabama. An upper-level disturbance led to the development of a line of strong storms, which would march eastward and lead to wind damage and a couple of tornadoes early in the morning across these states. However, this would not be the main event of the day, but it did cause issues which contributed to how dangerous and destructive the afternoon would be.
The radar loop above is from the National Weather Service in Huntsville, Alabama, showing the line of storms which moved through early in the morning.
Though not the main event so to speak, this line of storms was quite potent and also damaged communication infrastructure in some areas, which made it more difficult to disseminate warning information and communicate in general.
A secondary round of storms occurred later on the morning of April 27 which also brought some tornadoes as well as wind and hail.
The main event:
By early afternoon on the 27th, the atmosphere had ‘reloaded’ so to speak. Wind shear and moisture values increased dramatically ahead of the cold front and combined with strong instability values, led to the development of numerous supercell storms, many of which produced violent and destructive tornadoes.
By 2 to 2:30 p.m. in the afternoon, supercells were ongoing across the states of Mississippi, Alabama, and Tennessee. These storms moved northeastward traveling fast. The radar image above shows the signatures of many of these storms with classic ‘hook echo’ signatures. The extremely rare combination of the amount of wind shear and instability led to nearly all of the supercells that formed in these areas producing tornadoes, though some of the tornadoes were stronger than others.
These storms and associated tornadoes brought devastation to many communities in the Deep South, but it wasn’t limited to just those areas. Tornadoes were reported as far south as Florida and as far north as New York, although the worst of the damage would be in Mississippi, Tennessee, and Alabama.
There are a few notable tornadoes from this outbreak that I would like to dive into a bit more. I have chosen two in particular due to their strength and also their paths, which moved through populated areas.
Tuscaloosa-Birmingham EF4:
This tornado is arguably the most well-known of the outbreak. It impacted both the city of Tuscaloosa as well as the northern areas near Birmingham, Alabama.
It was produced by a supercell that began in Mississippi, producing several strong to violent tornadoes along its path, including this one, before finally dissipating in North Carolina.
This particular tornado touched down at 4:43 p.m., traveling for 80.68 miles, before lifting at 6:14 p.m. to the northeast of Birmingham.
At its peak, the tornado reached a width of 2,600 yards, or 1.5 miles wide. It had peak wind speeds at an estimated 190 mph.
Numerous buildings were swept clean off their foundations. Some concrete slabs were also wiped clean. Extreme tree damage was also noted.
This photo taken by the National Weather Service in Birmingham, Alabama, shows the visible trail of destruction from the air.
In total, this tornado was responsible for 65 fatalities as it moved through Central Alabama and 1,500 injuries.
Northern Alabama EF5:
This tornado, one of the most powerful of the outbreak, began in Marion County, Alabama, at 3:28 p.m.
It impacted multiple communities, causing devastation in small towns such as Hackleburg and Phil Campbell. It continued through multiple Northern Alabama counties, causing extreme damage to other communities, including areas just west and north of Huntsville, Alabama.
At its strongest point, extreme damage occurred. Homes were completely wiped clean off their foundations. A large cargo container was picked up and blown approximately 600 yards. Several cars were also carried airborne for hundreds of yards.
The tornado was also captured by a tower camera on top of Huntsville TV station WAFF-48′s radar tower in Limestone County before it took a direct hit from the tornado.
At its peak, the tornado had a width of 1.25 miles wide. It was on the ground for 132 miles before it finally lifted after crossing into Tennessee. It had estimated peak winds of 210 mph. Due to the incredible damage recorded along the path of the tornado, it was given a rating of EF5.
72 fatalities and at least 145 injuries were attributed to this tornado.
Some personal thoughts:
First of all, I would like to thank all the National Weather Service offices in Huntsville, Alabama, Birmingham, Alabama, and Jackson, Mississippi, for their extensive archiving of this weather event.
I would also like to give a special thanks to Huntsville, Alabama station WAFF-48 for providing an image.
There are so many things that could be said about this outbreak and this article could be some much longer, but I decided to do a general overview of the event as well as focus on two of the tornadoes in particular. There were so many others that could be dived into, but I decided to talk about the two that I talked about in particular.
I was in my latter years of high school when this outbreak occurred. As a young weather enthusiast, I was absolutely astonished by what I was seeing. When I saw pictures of the aftermath, I was horrified by what I saw.
My heart goes out to all those who lost loved ones in this disaster. I also want to thank and remember all the first responders, journalists, meteorologists, and others who worked diligently to protect and save lives during this disaster.
I hope an outbreak like this doesn’t happen again for a very long time.