Map Stories – April 27, 2014 Tornado (Mayflower and Vilonia, AR)

This Entergy substation SW of Mayflower received a direct hit from yesterday's tornado.  Click the image to view the preliminary track of the storm

This Entergy substation SW of Mayflower received a direct hit from yesterday’s tornado. Click the image to open an interactive map for this point as well as other areas along the damage path.

It’s April again and that unfortunately means it’s tornado season.  Clicking the image to your right will take you to an interactive story map showing the tornado path for this storm, with links to videos, pictures and other supporting information.  The story shows a step by step view over a 60 minute period during the life of this tornado.

This storm rotation path is based on NWS Weather Radar observations.  Points were added to depict the center of rotation at roughly five minute intervals as the radar updated.  Those points are then connected to depict an approximate rotation path, which is then buffered on each side to depict a 1/4 mile, 1/2 mile and 1 mile wide area.  The tornado width has not yet been determined by NWS Little Rock, however these ranges help to depict likely impact areas, with the most likely impact area being the 1/4 mile wide corridor (red area), followed by the orange area (1/2 mile wide corridor) and finally the 1 mile wide corridor (yellow area).

Additionally, the damage photos and videos were added to the story map AFTER the damage path was created.  This means that as videos and pictures are reported to/by local media, social media, emergency managers, etc., the location of the photos can be compared against the preliminary estimated damage path in order to verify the accuracy of the information.

The preliminary impact corridor is essentially serving to identify the hazard zone.  On top of that map, information on community facilities, demographics, etc can be overlaid, thus creating an realtime operational impact analysis or risk assessment.  That in turn can be used to help refine the response to the hazard so the community can respond and then recover as fast as possible.

When you don’t know the impact zone of any natural disaster, it’s nearly impossible to get your arms around the situation and make sure that the appropriate resources are being called upon to assist in the response.  However when the impact zone is clearly identified, it can facilitate improved collaboration and effectiveness of the response – from individual citizens and neighbors, to community groups, charities and finally local, state and national officials.

If you find this resource helpful, please pass it on to others.  Thanks.


Interactive ESRI Story Maps view of the April 27, 2014 tornado that impacted Mayflower and Vilonia, AR.



Deadly Tornadoes Cut Through Central Oklahoma (Edmond, Carney, Norman, Bethel Acres, Shawnee)

Earlier this evening, several supercells erupted in Central Oklahoma, producing several strong to violent tornadoes.  These tornadoes impacted communities such as Edmond, Carney, Norman, Bethel Acres and Shawnee.  Much of the attention now including prayers have been focused on those impacted in a mobile home park directly in the path of the tornado where at least one fatality has occurred.

The following link goes to an interactive map showing the approximate paths of the three most significant tornadoes that impacted Central Oklahoma.  The map has a bookmark feature where you can view the Edmond, Carney and Norman to Shawnee tornadoes.  Similar tornado path maps have been very helpful and highly accurate for other significant tornadoes events over the past several years.

Click on the graphic to launch an interactive map.

Click on the graphic to launch an interactive map. The map contains bookmarks for the 3 tornadoes as well as an address lookup feature.

This information is unofficial information, but is based upon NWS Radar scans and uses the National Climate Data Center Weather/Climate Toolkit (NCDC WCT) and ESRI’s ArcGIS Online.  For official storm survey results, please follow the National Weather Service in Norman, Oklahoma (@NWSNorman).  In the coming days, the National Weather Service will be performing storm damage surveys.  When more information is made available, I’ll be linking to those products.

Radar Derived Storm Paths from the 4/14/2012 Tornado Outbreak

Click the Image to Open an Interactive Map Depicting Rotation Paths for Spotter Confirmed Tornadoes

[UPDATED: 4/17/2012 – 12am CT – Several National Weather Service Forecast Offices have completed preliminary storm surveys.  The product I created Saturday evening has been verifying very well, especially with the long-tracked storms.  Comparisons will be added for each tornado below.]

First off.. my thoughts and prayers are with all those impacted by today’s tornadoes, especially in Kansas, Oklahoma, Nebraska and Iowa.  I’ve put together path tracks of the tornadoes based on radar data.

I hope this has helped some people today save lives, and in the days to come, I hope it helps people recover faster from the storms.

Below is an interactive map that is based on spotter confirmed significant tornadic storms.  The points on the map UNOFFICIALLY depict the most likely areas where a tornado went based on radar products from the National Weather Service.  It will likely take several days for authorities in the area to fully assess the damage, but in the mean time, I hope this helps people as a starting point.  Once official damage surveys are released, I’ll be merging them into the map. Also, please note that while the radar may indicate a continuous path, detailed damage assessments and storm surveys may end up splitting these storms into separate tornadoes.

Continue reading

Preliminary Path Estimate for the 4/13/2012 Norman, OK Tornado

Preliminary likely tornado path created at 600pm CT

This post covers the Friday 4/13/2012 tornado that impacted Norman, OK in the evening hours.  The tornado outbreak continues into Saturday.  For the newest blog post covering the Saturday, 4/14/2012 Tornado Outbreak with interactive map, Click Here. (THIS INCLUDES THE PATH OF THE WEDGE TORNADO SW OF SALINA, KS)

4/13 – 1028pm CT – Added link to NWS Norman preliminary UNOFFICIAL track map from @NWSNorman

4/13 – 928pm CT – Updated interactive map to include links to media video and photo of damage with locations.  The locations verify quite well with the initial map points

It’s incredible to think of how today progressed…. First I shared a presentation on this topic to several of my peers around the country to share a methodology with the hopes of helping people tomorrow and in other tornado outbreaks, and the next thing I know, I’m talking to my brother in Oklahoma who is trying to get home to Norman after school, with a tornado warning for his home town.  It’s amazing to see the impact of how technology and information can be brought together to help protect lives.  I ended up helping guide him home to keep out of the storm while the tornado passed less than 1/2 mile from his house, telling him to stay put and keeping him out of harm, but still guiding him home.  Thankfully everyone in the family is safe, but it’s incredible to know that it makes a difference so close to home.

Continue reading

Preliminary Radar Based Rotation Paths – Devine, Natalia, Lytle, TX

During the evening of March 19, 2012, numerous supercell thunderstorms were observed across portions of the Southern Plains.  One of these storms impacted areas just southwest of San Antonio, TX near the towns of Devine, Natalia and Lytle, TX.  While further from the radar site (~60 miles from the radar in Austin, TX), the rotation signatures are definitely present on radar.  Additionally these signatures and their paths are typical of a supercell thunderstorm that “cycles” – essentially where one area of rotation weakens, and a new area of rotation emerges.  Note the time stamps (UTC times) and follow the intersection of the red/green colors along the path as the radar animation progresses.  Also, note how the paths curve to the left before weakening, and then a new area of rotation emerges to the right of the old one.  This is quite typical of a supercells that cycle.

We’ll learn more in the morning and as tomorrow progresses, but if I was to make an educated guess on the areas potentially impacted, they would be as follows: Continue reading

Radar-Based Maps of the Henryville, IN Storm Tracks

NWS Louisville Statement on the Challenges in Damage Assessment for the Henryville, IN Tornado.

UPDATE: MARCH 6 – The National Weather Service in Louisville has published their initial findings including descriptions of the areas impacted.  That information is available at: NWS Louisville Damage Surveys – March 2, 2012.

Also, I have put together an initial version of an interactive web-map at that combines information from the second map below with the damage path information from the NWS in the link above.  The map is accessible at: Web Map of the Henrysville damage path and radar based-storm tracks at

ORIGINAL POST: March 4, 2012 – 630pm ET:

The past two days have been full of media reports, tweets and information being shared on the tornado outbreak that occurred on March 2nd, 2012 affecting towns like Henryville, IN.  As you can see from the statement below from the NWS Louisville Forecast Office, there were two supercell storms that impacted the area, with the first one producing the tornado that most people are talking about.  There was in fact a second storm behind the first one that also produced tornadoes and tornadic damage.  To make things more complicated for damage assessment teams, the paths essentially paralleled one another, and even crossed in places, making it difficult to attribute the damage to one storm versus the other.

I’ve put together the following the following map based on the NWS Radar information from the March 2nd tornado outbreak.  The map shows the paths of the two storms and paint the clear challenge that the NWS professionals have in identifying and differentiating between the two damage paths. Continue reading

Tornado Fatailities and the NWS Dual-Polarization Radar Upgrades

One of the fatalities occurred in this area near Jackson Gap. The NWS warnings for this storm were very clear, telling people to “seek shelter underground” and that a debris signature was appearing on radar.

Some people might ask is it worth it to upgrade the National Weather Service (NWS) radars to this “new” dual-pol technology.  While only 25% of the 160 radar sites around the country have been upgraded, the performance in the March 2, 2012 Tornado Outbreak is quite an impressive statement to the effectiveness of the technology.

During the March 2nd tornado outbreak, many of the tornadoes occurred in areas where the radars have already been upgraded.  When the debris was detected by the dual-pole technology, meteorologists could enhance their tornado warnings, confirming that a damaging tornado was indeed on the ground.  These signatures are essentially as good as visually confirmation of the tornadoes being on the ground.  The technology works because when the radar beams hit debris (leaves, shingles, branches, parts of houses, etc), there is a different signature from what is seen by the radar.  In the graphic above, you can see the blue area in a circle.  This area means that the radar is seeing a “different” signature from the surrounding areas.  When this is in the same location as strong rotation as seen by the doppler velocity products, it is essentially a confirmation of a tornado on the ground at the time of the radar sweep, or just before that time.

This will be significant with difficult-to-see tornadoes, especially ones that are either rain-wrapped or occurring in the overnight hours. Continue reading

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.

Continue reading

NCDC Weather/Climate Toolkit BETA v 3.5.0 Released

The beta version of the National Climate Data Center (NCDC) Weather and Climate Toolkit (WCT) has been released and is now available for download from  This beta release adds support for several new functions including Level 2 and Level 3 Dual-Polarization products like the graphic below.  The tool is available for use in Windows, Mac OS/X and Unix/Linux environments.  I personally use the standalone download because it’s easier to save versions locally to test out the features of the newer release. Continue reading

Radar/Satellite Loops of the 10/17/2011 Lubbock, TX Haboob

In the afternoon of October 17th, there was a significant dust storm that impacted the Lubbock, Texas area. This dust storm or “haboob” has caused at least 17 reports of winds above 50kt (58mph).  Below are several views of the data from various sources: