Friday, May 17, 2013

The Tornado Chronicles: Granbury and Cleburne TX Tornadoes of 5-15-13...

Thus far, 16 tornadoes have been confirmed across North Texas during the late afternoon and evening hours of May 15, 2013 as several supercell storms produced multiple tornadoes and/or tornado families.  

The two strongest tornadoes took place just to the East of Granbury (in Hood County - as shown in the photo above) and in the Cleburne area (in Johnson County).

A preliminary track map for the Granbury area tornado is shown below.  the first map is a wide view, and the second is a tighter zoom on the track itself:

The tornado to the East of Granbury had a track length of 2.75 miles and the damage is preliminarily rated at EF-4 intensity, with maximum winds of 166-200 mph.  

The video below, posted to YouTube by "tsubasachan777" shows the tornado at about the time that the EF-3 to EF-4 intensity damage was being done.  WARNING: turn the volume way down - the wind is very loud as it blows across the open body of water in the foreground:

The damage from this tornado is extensive and very impressive.  Several
frame built homes (not mobile or pre-manufactured homes) were wiped completely off of their foundations, which signifies high end EF-4 or low end EF-5 intensity damage (depending on how the home was originally secured to the foundation):

Numerous other homes were heavily damaged and/or completely destroyed in widespread EF-3 or EF-4 intensity damage:

A mapping of the Cleburne area tornado is not yet available (please check back to this post for updates).  The Cleburne area tornado track was 8.5 miles in length and the damage is preliminarily rated EF-3 intensity, with maximum winds of 140 mph.

At one point it is estimated that the tornado was as much as 1 mile wide, as suggested by this frightening video (as the huge tornado is illuminated by nearly continuous lightning) posted to YouTube by storm chasers Bill Ford and Mike Casey:

This is the same supercell storm that made a near "U-turn", first travelling to the South/Southeast and then turning back Northward toward the Cleburne area, producing one or more tornadoes all the while.

While it is not unsual for a severe thunderstorm to make a right or left turn over time, it is relatively rare for such a dramatic shift in direction to take place in such a short period of time as we saw near Cleburne on Wednesday evening.

Numerous homes were also heavily damaged or completely destroyed in the Cleburne area as well:

The aerial footage shot by KXAS TV is even more telling of the damage that took place in this region:

There has been some discussion since the event that it was "not forecast" or "under forecast."  While its true that the National Weather Service initially issued a Severe Thunderstorm Watch for the region on Wednesday afternoon, the watch was upgraded/converted to a Tornado Watch shortly before 6pm, roughly 60-90 minutes before the first of the stronger tornadoes started to develop.

The overall meteorological situation on Wednesday very much reminds me of the situation that we saw two years ago in the Joplin area.  The situation rapidly evolved during a relatively short period of time and became very favorable for intense tornado development over a relatively concentrated geographic area.  Unlike the situation shaping up for this weekend in the Plains, where tornadic development appears likely several days in advance, it is the type of events that took place on Wednesday night that we seek to learn more about in order to increase their longer range predictability in the future.

If you have an interest in the tornadoes that took place in the Granbury, Cleburne and North Texas areas on Wednesday, please bookmark this post and check back for updates that will be forthcoming over the next few additional information is received.

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Anonymous said...

That's a pretty dramatic turn to the north on the Granbury track. What would cause it to do that?

Anonymous said...

thanks for share......

Vernell said...

This is cool!