Thursday, April 05, 2012

Tornadoes In Texas...It's April After All

Dallas' tornado event on Tuesday is not unusual for this time of the year.  Thankfully, nobody died from the tornado event down there on Tuesday.  However, the localized tornado outbreak resulted in at least eleven touchdowns throughout North Texas, three of which went through the Dallas-Fort Worth metroplex as EF-2 or stronger twisters, which indicates the potential for significant damage and winds of at least 111 miles per hour within the twister itself.

The tornadoes were strong enough to pull some trailers up into them (see video below) and toss them into surrounding housing developments.

The outbreak could have been much worse and if a tornado hit the wrong place at the wrong time, significant casualties could have occurred. "It looks like the Dallas-Fort Worth area really dodged a bullet," Dallas Mayor Michael Rawlings told CNN. "I mean we've got hundreds and hundreds of homes destroyed but amazingly no fatalities."

With the twisters moving through during the day while many are off at work and school, the number of individuals residing in their homes was lower than it would have been had these tornadoes moved through at night.

Tornado climo for April (courtesy NOAA)

Texas receives the most tornadoes statistically during the month of April, an average of 28 per year between 1981 and 2010.  Obviously, being a big state helps pad that number a bit but even neighboring Oklahoma and Kansas are among the top tornado states in April so state size alone is not the only consideration.  Its location, near the Gulf of Mexico and to the east of the Rockies, provides a great geographic setup for moist winds to interact drying winds coming down from the mountains.  Low pressure moves into this area and will interact with the Gulf moisture to develop thunderstorms along the frontal boundary, with the prospect of tornadoes occurring in the strongest of storms.

April and May are "prime time" for severe season in the Plains and North Texas -- so from a time of year perspective this outbreak is not unusual.  However, the lack of loss of life is a bit out of the norm given the population impact.  The next tornado event in a highly populated area may not have a similar outcome.