Why was the flooding in Texas so deadly?

Economist

a day ago

Graphic detail | Water fall
A mixture of geography, catastrophic rainfall and a lack of preparedness
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More than 100 people have died in one of the worst floods to hit America in a century. Torrential rain swept through Kerr County, in central Texas, early on July 4th. Among the dead are 27 girls and staff members carried away from a Christian summer camp as the water surged. More heavy rain is forecast this week. The charts and maps below explain what made the flood so deadly.
Flash Flood Alley
Texas
Texas Hill Country
Ingram weather station
nty
Kerr County
Hunt water gauge
Guadalupe river
Camp Mystic
Guadalupe
river basin
50 km
Part of the cause was record rainfall in a particularly vulnerable area of the state. At the Ingram weather station near Camp Mystic—where the girls had been staying—more than 13cm (5 inches) of rain fell in 24 hours, nearly double the historical average for the whole month. In some nearby areas of Kerr County, as much as 25cm may have fallen in just a few hours.
The location of the downpour—at the head of the Guadalupe river—amplified its effects. Between 2.30am and 5.10am on July 4th the river rose almost nine metres (29 feet) at the Hunt water gauge near Camp Mystic. At 5.10am the river reached over 11 metres, after which the gauge stopped working for several hours. At this point more water was surging through the river than the typical flow over Niagara Falls. These levels surpassed those of a deadly flood in July 1987, when ten teenagers died while evacuating from another camp.
Kerr County and the broader Hill Country region lies in 'Flash Flood Alley', a band of central Texas that curves south from Dallas through Austin, then west via San Antonio to the Mexican border. Warm, moist air from the Gulf of Mexico rises over the cliffs and hills of the Balcones Escarpment. It then cools and condenses into heavy rain. This natural mechanism makes the region unusually prone to downpours, says Hatim Sharif, a hydrologist at the University of Texas at San Antonio. This weekend the amount of water vapour rose because of remnants from Tropical Storm Barry, which made landfall in Mexico on June 29th.
The landscape compounds the danger. Semi-arid soils soak up little water. Rain races down hills into a dense network of narrow creeks, which rise quickly. When the water surges it can sweep away buildings, vehicles and people. That danger is well known to Texans: their likelihood of dying in a flood is twice that of the average American. Between 1959 and 2019 more than 1,000 people in Texas were killed in floods—the highest death toll of any state.
Watermark
Deaths from flooding, 1959-2019
200
400
600
800
Texas
1,069
Despite the forecasts and its history of flooding, Kerr County appeared unprepared. Local news reports note that the area still lacks a flood-alarm system to notify residents and visitors: efforts to fund one have failed since 2018. The timing of the floods—in the middle of the night—may have made it harder to spread warnings and evacuate.
Questions are also being asked of the Trump administration and its Department of Government Efficiency (DOGE). Since January the National Weather Service (NWS) has lost around 560 staff—through sackings, early retirements and voluntary redundancies—reducing its workforce by 10%. Some of these roles now need to be rehired. The NWS's offices in central Texas have unfilled posts for important positions, including a senior hydrologist and a warning-co-ordination meteorologist.
In an open letter published in May, former directors of the NWS who served between 1988 and 2022 warned that their 'worst nightmare' was for staffing cuts to result in 'needless loss of life'. It is not clear yet what role, if any, the budget cuts may have played. It is, however, clear that flash-flooding will continue. Basic physics means that hotter air holds more water; on a warming planet that means increases in extreme precipitation of all sorts.