Springtime is severe weather in Texas, so it is not unusual to see thunderstorms, hail, and tornadoes this time of year. What has been unusual is the frequency and severity of the severe weather. A brief survey of the storm reports for Texas available at the National Oceanic and Atmospheric Administration’s (NOAA) Storm Prediction Center (SPC) revealed sixteen days in May with at least one kind of severe storm hazard.
These storms have caused widespread power outages, damage, and disruption and have created dangerous conditions. Damage to infrastructure, especially electrical transmission lines, has been significant, which adds to the challenges Texas is facing regarding the electrical grid going into what promises to be a hot summer.
Houston Derecho
The Houston area was rocked by what was later determined to be a derecho, an unusual type of windstorm that forms from an organized complex of thunderstorms. The National Weather Service classifies a storm as a derecho “if the wind damage swath extends more than 240 miles (about 400 kilometers) and includes wind gusts of at least 58 mph (93 km/h) or greater along most of its length.”
The derecho that hit the Houston area on May 16-17 caused an estimated five billion dollars in damage. Images of crushed transmission towers indicated the power of the winds, which exceeded hurricane force in several places. The destruction of transmission infrastructure meant that electricity was out for thousands of people for several days. Tragically, the derecho also caused seven fatalities due to falling trees and collapsing buildings
The derecho also caused significant damage to the glazing (exterior glass) on several skyscrapers in downtown Houston. Windstorms damage high rise buildings by lofting debris that then acts like a missile when it impacts windows and other building components. This is a particular problem for skyscrapers because of the way wind speeds are higher further off the ground. The images of damaged skyscrapers after the Houston derecho were eerily reminiscent of hurricane damage.
Space City Weather has a great article about the Houston derecho, including a meteorological discussion and historical analysis.
North Texas Hail and Tornadoes
If the story was water and wind in Southeast Texas, tornadoes and hail were the story in North Texas. SPC reported tornadoes on six days and hail on nine days in May. The most serious severe weather occurred on Sunday (5/25) when four tornadoes touched down north of Dallas, destroying homes and causing seven fatalities.
Hail in an area as populated as the DFW Metroplex can drive up the economic cost of a severe thunderstorm rapidly. The city has seen multiple rounds of severe hail this month with significant damage to roofs and vehicles likely.
Also driving up the economic impact of these severe thunderstorms is power outages, which are inconvenient and disruptive, but also lead to secondary losses like loss of food in refrigerators and freezers, interior mold in homes, lost productivity and work hours, and major challenges for people who rely on electricity to power medical equipment.