(Caution: Image heavy)

I think we've all seen those disaster shows on the science channels at one point or another. You know the ones..."It Could Happen Tomorrow" on The Weather Channel, or one of the three zillion shows the Discovery Channel runs just to keep their CGI department in business. They run the gamut of disasters, and one of the recurring scenarios for them is an EF-5 tornado tearing through a major populated area.

That's exactly what happened at about 5:30PM CDT on May 22, 2011. The deadliest tornado in 60 years, and the costliest tornado in American history, struck Joplin and wreaked damage that makes one shiver just thinking about. 161 people lost their lives, over 8,500 buildings were destroyed or damaged, and $2.8 billion in damages were reported in the worst single tornado to hit the United States in over a generation.

The Joplin tornado.

May 22, 2011 was an ominous day for severe weather watchers.  A powerful low pressure system was swirling across the Great Plains with a strong cold front stretching down the Plains into northern Mexico.

The severe weather parameters the morning of the 22nd were through the roof. The 7:00PM CDT weather balloon sounding at Springfield, MO showed a MLCAPE (Mixed Layer CAPE -- essentially a measure of the "fuel" in the atmosphere that thunderstorm tap into to form...the higher the number, the stronger the storms) of 5000 J/Kg, which is ridiculously high. SRH (storm-relative helicity, or the amount of rotation a thunderstorm can develop based on wind shear) was approaching 500 m2s2  in Springfield at the 7:00AM weather balloon sounding.

In response to these very high severe weather parameters, the Storm Prediction Center issued a moderate risk for severe weather for a large part of the Midwest that afternoon for the risk of very large hail, damaging winds, and damaging tornadoes.

Early in the afternoon, strong thunderstorms began forming along the cold front from Kansas northward into the low pressure system. I remember admiring how photogenic the visible satellite image looked that afternoon, so I saved it, not knowing the destruction that would occur just a few hours later. The storm circled in red was the storm that went on to produce the Joplin tornado.

Below is a pseudo-case study of the radar images before and during the Joplin tornado. Here's an animation of the storms, with each frame dissected below.

The following radar image is from 5:00:22 PM CDT on May 22nd, showing a cluster of supercell thunderstorms moving through southeastern Kansas into southwestern Missouri. The supercell circled in red was the Joplin storm. Each of these storms were producing large hail at the time, and some were acquiring rotation.

This radar image depicts the Joplin supercell at 5:10:01 PM CDT as it begins to somewhat separate from the cluster in which it formed. As seen in the animation above, the cluster of supercells was moving east, but the low-level winds were hauling off towards the northeast. I believe that given the extraordinary severe weather parameters present that allowed for the formation of major tornadoes, the separation of this supercell from the other storms, as well as storms to the southwest merging into the main supercell, the environmental setup was complete for a very large, violent tornado to form within the supercell. It was only a matter of when and where.

This was at 5:29:21PM CDT when the supercell was rapidly strengthening and taking on a large amount of rotation. The image on the left is the base reflectivity showing the precipitation within the storm, and the image on the right is the base velocity image, showing the winds being detected by the radar. Keep in mind that the radar beam is approximately 4500-5000 feet off the ground by the time it reaches Joplin (due to the tilt of the beam coming off the Springfield, MO radar, and the curvature of the earth).

The arrows show the rear flank downdraft and the inflow air rushing out of and into the storm, respectfully. The left arrow is the rear flank downdraft (or RFD for short), which occurs when upper-level winds hit the strong updraft in the storm and get "stuck" with nowhere to go, so they turn down towards the ground, and wrap around the backside of the supercell. The inflow notch, depicted by the right arrow, is the warm, unstable air rushing into the updraft of the storm, feeding it like gasoline. The RFD and inflow jet tend to strengthen as rotation within a supercell increases, as was happening at the time of this radar image.

The base velocity image on the right shows red and green colors. Red signifies wind moving away from the radar (towards the west), and green signifies wind moving towards the radar (towards the east). When the red and green colors come in close contact to each other within a thunderstorm, as they are in this image (look at the tip of the inflow jet arrow), this indicates strong rotation within a storm. The stronger the rotation, the more likely a tornado is occurring.

This next image was taken at 5:34:11 CDT and shows a rapidly maturing supercell wrapping up even tighter than just five minutes ago. The RFD has advanced towards the east into southwestern Missouri, and the inflow jet has tilted correspondingly. The circle on the base velocity image shows the counterclockwise rotation within the storm.

According to the NWS storm survey, the tornado touched down at exactly this moment.

The tornado was doing extensive damage by 5:39:01 PM CDT, the time of the following radar image. The storm is collapsing at this point, meaning that incredibly heavy rain and large hail has fallen through the RFD and inflow jet, making them harder to spot on radar. The circle on both the reflectivity and velocity images shows the tornado. As was stated by many Joplin residents and storm chasers, the tornado was almost completely wrapped in rain, making it hard and impossible to see from certain angles. This is why they stress not to wait until you can see the tornado, because sometimes you just can't. Plus, the tornado was so large that it just looked like a wall of black extending from the cloud to the ground.

On the left image (reflectivity), the white spot in the middle of the circle is a debris ball. A debris ball is when the radar actually detects debris -- wood, bricks, cars, people, trees, anything a tornado picks up -- and reflects the beam back to the radar where the software portrays it as extremely heavy precipitation.

At 5:43:51 PM CDT, the tornado was in Joplin bringing previously-unfathomable amounts of death and destruction to the city. The following base reflectivity image shows the impressive radar signature of the mile wide EF-5 tornado. The rear flank downdraft and inflow jet in the storm had merged at this point due to the incredible rotation within the storm, and the tornado had pulled the storm into a spiral.

This is the base velocity (wind) radar image from the same time as the above radar image, showing the winds about 5000 feet above the surface of the earth. This is only the second time in my life I had seen a storm spike out the limits of the radar imagery -- the other time being the Tuscaloosa/Birmingham tornado that occurred about a month earlier. The winds depicted in this radar image are not the maximum winds in the tornado. Based on the damage, the NWS rated the twister an EF-5 with winds exceeding 200 MPH at times.

By 5:48:41 PM CDT, the tornado had moved just east of the City of Joplin, and was beginning to choke itself off by ingesting cooler, more stable air. As seen by the base reflectivity image below, the debris ball was massive in the mile-wide twister -- almost 3 miles wide 5000 feet off the ground at this point. The debris in the tornado extended much farther than the actual funnel itself.

The velocity image from the same time is just as chilling, with the winds in the storm still spiking out the limits of the radar.

By 5:53:30 PM CDT, the tornado was beginning to weaken and lift back up into the storm. The massive debris ball -- literally the people and buildings of southern Joplin -- were still suspended in the atmosphere at this point, hence the large blob of white/magenta on the reflectivity image.

The velocity image shows the choking off and weakening of the tornado by showing a still impressive but dramatically weaker circulation associated with the tornado.

The storm went on to produce another EF-2 tornado in extreme northern Arkansas about 20-30 minutes later.

The following image is a damage survey done by the NWS, showing the width and extent of the worst damage in the Joplin tornado. The numbers in the triangles correspond with the Enhanced Fujita Scale rating given to the damage at the location pinpointed by the Weather Service. Click the image to open a new tab/window and read the NWS' storm survey for this tornado.

Not only did the storm scar the lives of the people impacted by the storm, but it also scarred the land. Given the intensity of the tornado, it stripped the bark off of and defoliated the trees in the area, tore grass and shrubs out of the ground, and in some places, even scoured the pavement right off the earth.

The Weather Channel was in the middle of its "Great Tornado Hunt" when the Joplin tornado happened, and meteorologist Mike Bettes and his crew happened to be tracking this very storm. Consequently, they were the first ones on the scene within a few minutes of the tornado tearing through. Bettes filed the following live report, which I must warn you is hard to watch.

The tall building in the background of Mike Bettes' emotional report is Mercy Hospital, which took a direct hit from the EF-5 tornado. The entire building was shifted off of its foundation, and the building was so heavily damaged inside and out that it was declared a total loss.

Here's security camera footage (released just the other day) from the hospital as the tornado hit:

And here was the result:

Photo credit: Samuel E. Warren Jr

They've since begun to tear the battered Mercy Hospital down, and the replacement is expected to be completed by mid-2015.

The following two videos were taken from surveillance camera footage at Joplin's East Middle School and Joplin High School, respectively.

A family who lives very near Joplin High School took a first-person video as the tornado ripped apart their home and neighborhood. Caution: strong language and may be hard to watch/listen to.

In all, 161 people lost their lives in this devastating tornado, making this the deadliest single tornado to hit the United States in almost 60 years. The NWS estimates that 75% of Joplin was damaged or destroyed in the tornado -- with 7,000 buildings completely demolished and 850 more damaged but repairable.

Joplin has proven resilient, rebuilding and growing from scratch in most cases. All schools that were damaged or destroyed have been relocated for now to locations that were renovated to accommodate classrooms, such as existing (but abandoned) schools, malls, and other large venues.

Joplin High School had their graduation at a nearby university the other night just shy of the one year tornado anniversary, and the event was both somber and celebratory. President Barack Obama visited the graduation and delivered the following moving commencement address:

The Joplin tornado will go down as one of the worst natural and human disasters in American history. The disaster was a double-edged sword. The National Weather Service issued a tornado warning on the storm almost 20 minutes before the tornado struck the city, and the tornado sirens sounded multiple times within Joplin. Resulting research has found that many residents of Joplin actually ignored the tornado sirens because of the frequency with which they go off (the "crying wolf" effect). The way in which many of the homes were built also played a role in the large amount of fatalities in a tornado, given that many homes in the area don't have basements. However, not many structures can survive 200 MPH winds and debris larger than vehicles impacting the structure they're in, either. Things could have been done to tamp down the casualties a bit, but hindsight is 20/20, and a tornado of this size hitting such a heavily populated area is going to wreak havoc and cause large amounts of death no matter how prepared a town is.

It's important to keep in mind that if the tornado had struck 10 miles to the north or south, the outcome would have been dramatically different. Would we know it was an EF-5 tornado with 200+ MPH winds? It's hard to say. Would we even remember it? Again, it's hard to say. The Enhanced Fujita Scale estimates the intensity of tornadoes based on the damage it produces. The tornado received its EF-5 rating because it scrubbed clean to the foundation well built homes, and gutted and shifted an entire hospital building off of its foundation. Even if it had missed Joplin, and the environmental conditions were the same, the tornado likely still would have had 200 MPH winds. Tornadoes that hit heavily populated areas such as Joplin tend to be rated stronger because they produce more surveyable damage than, say, a tornado that hits three barns in Kansas.

The Joplin tornado was a tragedy that hopefully we'll never see again in this country for a long, long time. We need to improve our warning systems, improve our building codes, and help better educate the public on how to appropriately react and respond to a tornado warning in a fashion that could save lives.

If you want to help Joplin in its continued recovery, you can give to the American Red Cross, or directly give to Rebuild Joplin, the official organization in charge of the recovery of the city.

Do yourself, your family, your friends, and even your frenemies a favor by getting S.A.M.E. enabled weather radios. These specially built devices act like fire alarms. When properly programmed, they sound a loud alert tone and actually read the text of the severe weather warning that was issued for your county.

If you don't want a weather radio, or already have one, search your local newspaper and TV station websites for severe weather text alerts. If you have an iPhone or an iPod Touch, download the iMapWeather Radio App. It's the best $9.99 you can spend. It acts as a weather radio by sounding a loud alert tone whenever your current GPS location (or pre-programmed locations) go under a watch or a warning.

AP/Tulsa World


President Obama visits Joplin a few days after the tornado.

A man rebuilds. Photo from Rebuild Joplin.

A rebuilt home in Joplin. Photo from Rebuild Joplin.

Originally posted to El Blogo de Weatherdudeo on Tue May 22, 2012 at 11:33 AM PDT.

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