National Weather Service United States Department of Commerce

On the evening of Sunday, May 10, supercell thunderstorms developed over portions of Brewster County.  Thunderstorms both north and south of the community of Marathon exhibited rotation and produced large hail.  Significant damage was reported east of Highway 385 and north of Farm to Market Road 2627.

In total, 44 distribution poles across a six mile area were damaged in this event.  Poles along western stretch of damage were snapped 3 to 5 feet above the ground.  This type of damage was seen for approximately four miles.  Lesser pole damage - poles snapped higher off the ground and then only crossbar damage - was seen in the remaining two miles farther to the east.   We would like to provide a special thank you to Dave Lassanske from Rio Grande Electric, who provided the following images and other key information contained within this damage survey writeup.

Damaged distribution poles north of Farm to Market Road 2627 in Brewster County.

Damaged distribution poles north of Farm to Market Road 2627 in Brewster County.

Based on radar imagery, and pole orientation the WFO Midland survey team determined that the damage was not indicative of tornado damage.  The damage was likely produced by severe downburst winds as the supercell thunderstorm began to "collapse" or weaken.  The following radar imagery shows an elevated  reflectivity core aloft at 0300Z on 5/11/09.  The second image shows the weakening storm several scans later.

0.5 Reflectivity from 0300Z - KMAF radar

0.5 Reflectivity from 0332Z - KMAF radar

Winds were estimated to be 90-100 mph with this straight line wind event.  Click the following Google Earth map to see the location of the damage area.  The entire six mile stretch remained within the Black Gap Wildlife Management Area, with the last damage noted just southeast of the Texas Parks and Wildlife Black Gap headquarters.

Storm damage area indicated in red on a Google map image