The seemingly endless and often torrential rains that deluged Texas and Oklahoma in May are in some ways a harbinger of what the South Central states can expect to see as the world warms. But the region also could be in store for just the opposite – more long bouts of hot, dry days that could cause the Southern Plains to be even more susceptible toMore
For the past few months, it seems Texas can’t catch a break from heavy rains and floods. Statewide rainfall has been well above average this spring as storm after storm has deluged the Lone Star state.
The latest system has brought historic flooding to parts of central and southeast Texas. The Brazos River reached a record height of 54.7 feet in the city of Richmond, Texas earlier this week. Located just southeast of Houston, this crest was more than four feet higher the previous record crest of 50.3 feet set in October 1994.
The big driver for this week’s round of rain has been a meandering area of low pressure in the upper atmosphere. This area of low pressure is cut off from the main jet stream flow, which has made its seasonal retreat northward toward the U.S.-Canada border. This leaves little movement in the atmosphere to push the system along, allowing it to repeatedly pour heavy rain as it draws in moisture from the western Gulf of Mexico.
This system will eventually drift southward and fade away, but that will not happen until the end of the weekend, meaning that soggy conditions will linger through Sunday. Going into Thursday evening, an additional 2-4 inches of rain are forecast through the weekend in parts of central and eastern Texas. The extra rain this week means it will likely take several days for the Brazos River to return to its banks in central Texas, and in places farther downstream, like Richmond, the flooding will likely continue for at least another week.
The rain this week was not the root cause of the extensive flooding. An exceptionally wet May set the stage for this week’s flooding, but high water has been a recurring theme in Texas through the spring.
The Brazos River watershed collects water from Fort Worth to Austin before spilling into the Gulf of Mexico just south of Houston. Areas between Austin and Houston have gotten more the 20 inches of rain since the start of May, which is about four times the normal amount. Further upriver, just southeast of Fort Worth, more than a foot of rain has fallen in May, more than twice the normal amount.
Heavy rain has saturated soils and kept rivers high, priming the area for the severe floods hitting this week. In parts of Texas such as Houston, heavy urbanization and other human factors have also led to the state’s recent watery woes.
While flooding is a normal occurrence in Texas, examining the frequency of heavy downpours in Texas indicates that these periods of more intense rain have become more frequent in recent decades. As the planet warms from climate change, there is more evaporation from both land and water surfaces. In turn, this leads to more water available for precipitation.
After the weekend, Texas will finally get a chance to dry out for several days. Some of Texas’s famous summer heat is likely to show up before the end of next week as well, keeping the state’s string of extreme weather running.