Case Study – 11/7/2011 SW Oklahoma Tornadoes – Radar Indicated Rotation Tracks


Below are several screen captures that I’ve put together showing the locations of the rotation couplets for the SW Oklahoma tornadoes. These are usually spot on with damage surveys [UPDATE: CHECK OUT THE NWS TRACK MAP AND COMPARE IT TO THE ROTATION MAP CREATED FROM RADAR DATA – IT WORKED AGAIN!!]. We’ll see how close they are, but since all points were within 30-40 miles of the Frederick, OK radar site, they’re likely to be less than 1/4 mile off from wher damage would be expected.

Why is this important you might ask.  In an event like this, meteorologists both in the broadcast media and with the National Weather Service are trying to warn people in the path of these dangerous storms.  They are concerned about where the rotation is currently, and where it is going – their emphasis is primarily on warning for the tornado.  However once the tornado has gone through a subdivision, that area where the storm has already tracked becomes the focus of the first responder and local emergency manager.  Many times, all they have to go off of are hundreds to thousands of 911 calls, coming from all over – or so it seems.

Wouldn’t it be great if emergency managers and first responders could know exactly which areas are being impacted, know which schools were in session, identify critical community facilities or mass gathering points, identify major highways and intersections that are affected, etc… etc…???  That world may seem far off, but this event proves again that during strong and violent tornadoes, radar detected signatures are usually strong enough to accurately locate where a tornado is located within 1 mile, and in most cases within 1/4 mile.  For the scientific community, this error is generally too big for warning purposes, however this margin of error is definitely acceptable for first response purposes.

Take a look at the following video and maps.  Look for geographic features that correlate – they’ll show up time and time again – railroad tracks, turns in the road and more. (Try starting at 2:40 in the video and watch until 2:54 when you cross the railroad tracks.  This will correlate with image 3 below on US-183 heading north – where the railroad tracks and road intersect).  Now, look at the last map showing the green circles.  Those circles show the rotation track (radar indicated rotation path).  The maps also show the NWS verified tornado tracks.  Note how close the radar indicated path and actual path are to one another.

Radar Indicated Rotation Path – Created 11/8 Before the Storm Tracks Were Verified by NWS Storm Surveys

Radar Indicated Rotation Path – Created 11/8 Before the Storm Tracks Were Verified by NWS Storm Surveys

Radar Indicated Rotation Path – Created 11/8 Before the Storm Tracks Were Verified by NWS Storm Surveys

While this is a technical product, it begs the question – when we collaborate and share information, are we sharing the view that is important to us, or are we sharing the actual information needed by our partners to do their job more effectively.  This type of product can be created within minutes of a tornado and can aid local emergency managers and first responders in overlaying critical local GIS datasets (mobile home parks, parcels, buildings, roads, public facilities, mass care centers, storm shelters, etc). That helps to build an operational risk assessment to better understand where to expect reports of potential damage, and additionally to help confirm that a tornado occurred.

By confirming damage in this corridor and matching it to the couplets, this helps the NWS and broadcast meteorologists to know that damage is occurring where a radar indicated tornado is seen. This in turn helps those two entities to enhance and upgrade the wording used to protect life and property in other towns downstream of the tornado. This process has worked time and time again for major tornadoes within 40-60 miles of radar sites, and has incredible application for focusing warning coordination efforts in some of the most at risk areas. Go ahead! Try it with historical radar data – pick a storm that has had significant damage in the past few years (Greensburg, Joplin, Oklahoma City, El Reno, Tuscaloosa, Raleigh, St. Louis, or many others).  Now see if that locality has GIS resources in their community or state that could benefit from this type of information.  You’ll see that this sort of information sharing (not just a map layer, but an answer to an operational question) is essential for rapid and appropriately scaled response.  When you see storms hitting urban areas like Joplin or Tuscaloosa with sustained damage signatures, there will likely be requests for USAR assets.  Likewise, the recovery will be long and hard, but coordination of impact and severity will be essential.  Again, we aren’t missing the technology – we have the technology already and we’re using it… but we do need to work to improve communication between the people and relevant processes.

By improving how WE ALL communicate and identifying existing resources, we can dramatically improve how we respond to these devastating natural disasters – coordination and communication that will ultimately save lives.

Comparison of Radar Indicated Rotation (circles) w/ confirmed tornadoes (line)

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One comment on “Case Study – 11/7/2011 SW Oklahoma Tornadoes – Radar Indicated Rotation Tracks

  1. Pingback: Case Study – 11/7/2011 SW Oklahoma Tornadoes – Radar Indicated Rotation Tracks | Disasters & Disaster Mapping | Scoop.it

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