Sunday, April 24, 2011

More on North St. Louis Tornado of 4-22-11

A large, damaging tornado struck northern portions of the city of St. Louis on the evening of Good Friday, 4-22-11.  The NWS in St. Charles has completed its damage survey and rated the tornado EF-4 intensity at its peak, in Bridgeton along Old St. Charles Rock Road.  There are many locations along the tornado's path with widespread EF-2 and some EF-3 damage.  The entire path length was 22 miles, and the tornado was as wide as 0.4 mile at some points along the path:

This next image is the same track map as above, with EF intensity ratings noted along the path (please note only EF2 or higher intensities are shown):

The image below is a reflectivity (rain, hail, etc.) shot from the St. Louis area radar, taken at 7:59 PM CDT, showing the tornadic storm as it approached the Champ area:

This next image is the same as above, only in velocity mode, which shows wind speed and direction.  Remember, reds show wind blowing away from the radar, while greens show wind blowing toward the radar site.  In this image, the radar site is located toward the bottom left corner of the image (at the light blue "KLSX" notation).  The apparent circulation is circled in white:

This next series of images show the tornadic storm as it approaches and moves over the Lambert Field/St. Louis International airport shortly after 8pm CDT.  The first is a reflectivity image taken at 8:08 PM CDT.  The Lambert Field weather observation site is located at the red dot near the tip of the white arrow.  The weather observer reported a tornado "on the ground moving East" in an observation completed at 8:14 pm CDT:

This next image is the same as above, only in velocity mode.  The apparent circulation is circled in white, and the weather observing site is noted as in the image above:

A strong radar indication of a "debris ball" began to appear to the East of the airport near Ferguson on the radar image taken at 8:16 PM CDT:

The white circle just to the East of Ferguson shows the higher reflectivities that appear to be associated with a debris ball.  This is structural and other debris being carried aloft by the tornado and reflected back to the radar, just as rain or hail would normally be reflected.

The following video is multi-part.  First it captures a tornado produced by the same storm near Weldon Spring, well to the West of Champ, along I-64 (time 0:00-1:30 on the video).  This particular tornado dissipated at some point before reforming just West of Champ, where it remained on the ground across northern portions of St. Louis.  You next see footage of the videographer(s) driving East into St. Louis toward Lambert airport.  You can't really see the tornado, but you can see power flashes as it causes damage (1:31-2:08 on the video).  Finally, you see video of the damage at Lambert airport: 

A raw video of aerial damage footage can be seen here.

The following photos show the extensive destruction caused by this tornado:

Believe it or not, no deaths and no serious injuries were reported as a result of this tornado.  Definitely a strong testament to the success of the early warning system that performed flawlessly across the area during this event.


Anonymous said...

My concerns is for familys' in St Louis Mo right now not a airport opening Sunday. People like you said our prayers are with them yet most are in shock trying to hold things together yet was it a week ago or few days St Louis had a close call your reporter was there did this storm take the same track as last week, because the sirens blew last week. There are warning signs before a storm you just know everyday I watch the weather morning, noon, and night have a plan weather channel, friends, neighbors you each can call each other keep everyone safe know your safe area, and how to prepare in any storm.

Shelia Rossell

Rob In Texas said...

I usually like to reply to comments left on the blog, but I really am confused by the comment from 'anonymous' Shelia.

I think you must have me confused with someone else. I didn't mention the airport re-opening, and I don't have a 'reporter' in St. Louis. I am a retired meteorologist and make blog posts about significant weather all across the country. I am in Texas, not in St. Louis.

I certainly do wish those of you in St. Louis the very best with the recovery effort. I am very glad to hear of the reports that no one lost their life in this event.

Carol in STL said...

Fantastic reporting, Rob. I live a few miles south of where the tornado went, and I really appreciate your maps showing what happened where.

FYI, and for all the people checking this blog, worried about relatives in St. Louis, the news reports this morning say there were NO serious injuries, miraculously.

Anonymous said...

The tornado was in suburban St. Louis County (a separate governmental entity),not the City of St. Louis. It hit towns of Bridgeton,Hazelwood, Berkeley, Ferguson, Riverview, etc. Why this is significant is that as bad as this tornado was, & it was bad, it still took place in communities far less heavily populated that most neighborhoods in St. Louis City. Many of us have gone to aid our friends and relatives living in these nearby communities and offered them our prayers & donations. We were extremely fortunate that no loss of life was preported with this weather event.

Anonymous said...

I don't know how many people outside of the St. Louis Metro Area that the "Good Friday Tornado" was the 2nd "holiday tornado" to hit this area. The other storm took place on Dec. 31, 2010, New Year's Eve. Of course, that storm was not as severe as this one, but it did some damage in one of the southwestern suburbs and actually damaged some houses in the middle of the City of St. Louis. St. Louis being situated in "Tornado Alley" gets its share of these storms, but I don't remember any year where 2 of these took place so close together (& we're only 4 months into the year).