Monday, May 23, 2016

5 Years Later- The Joplin Tornado

For the second time (and not the last) I am recapping a devastating tornado from 2011.  The first was the April 27, 2011 super tornado outbreak that killed 327.  That outbreak featured over 200 tornadoes.  On May 22, 2016 a single tornado killed 158 people and injured over 1000.  This made the Joplin, MO tornado the deadliest one in modern times (since 1950- a tornado in 1925 claimed over 600 lives).  
Joplin, MO tornado damage (image Wikipedia)
Sunday May 22, 2011 began with a moderate threat of severe weather in the Mississippi River Valley.  Many tornadoes formed but they were of course over shadowed by the Joplin event.  Here is the SPC risk and actual reports
SPC 5/22/11 severe weather outlook with actual reports
So how did such an event occur?  Let's start at the lower levels of the atmosphere and work our way up.
WPC Surface Analysis 5/22/2011 5 PM EST 
What we have here is a surface high pressure system along the Gulf of Mexico and a low pressure system in the upper plains.  The clockwise flow around the high was sending very warm moist air northward into the Mississippi River Valley/Midwest.  The counter clockwise flow around the low was sending cool dry continental air into the plain.   A little higher up in the atmosphere (~2500 ft) we can see the wind direction much better
SPC analysis 925 mb heights, temps, winds 8 PM 5/22/11
If you look closely you can see a wind shift or convergence zone near the OK/MO/KS border.  This created a favorable atmosphere for storm growth.  If we go further in the atmosphere to 18000 ft we find this
SPC analysis 500 mb heights, temps, winds 5/22/11 8 PM
Notice the wind direction is all southwesterly.  So we have winds turning with height.  This helped give the Joplin tornado tremendous rotation.  As a result at 547 PM local time the radar over Joplin looked like this
NWS Springfield radar 547 PM CDT 5/22/11
There was so much damage the radar picked up a debris signature.  Meteorologists watched in horror knowing that this wasn't a corn field it had just traveled over- it was a city with 50,000 people.  In all damage was estimated to be nearly $3 billion.
NWS Springfield, MO stats on tornado
The city is recovering but it takes a long time to heal from something as devastating as this.  We have a few anniversaries in New England coming up, one of which is on par with Joplin.

-Zack Green 

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