Climate change driving more rains that lead to deadly flash floods, experts say

Heavy Rainfall and Flash Flooding Increase in Parts of the US Amid Infrastructure and Regulatory Debates

Heavy rainfall has produced flash flooding across multiple US states in recent weeks, including Alaska, Missouri, New Jersey, New York, Ohio, Pennsylvania, and Texas. These events follow a deadly July 2025 flood at Camp Mystic in central Texas that killed 27 people. Experts have linked some increases in heavy precipitation to warmer air and ocean temperatures that raise atmospheric water vapor, though national precipitation records show mixed trends.

Data from the National Oceanic and Atmospheric Administration indicate that heavy precipitation events have risen in frequency in parts of the eastern and central United States over recent decades. At the same time, NOAA recorded the January-through-May 2026 period as the sixth-driest on record for the contiguous United States. Water vapor acts as a greenhouse gas and supplies additional moisture to storms, according to Jennifer Francis, senior scientist at the Woodwell Climate Research Center. This mechanism can intensify rainfall when storms occur, particularly in hilly terrain, urban areas with extensive pavement, and narrow canyons where runoff concentrates quickly.

Alice Hill, senior fellow at the Council on Foreign Relations, stated that much of the nation’s drainage infrastructure was designed for earlier climate conditions. Many cities continue to operate century-old sewer and stormwater pipes that lack capacity for current peak rainfall rates. Retrofitting these systems requires substantial time and funding. Hill noted that local resistance to the term “climate change” has sometimes slowed efforts to incorporate updated rainfall projections into project planning.

Development patterns have also contributed to flood exposure. In central Texas, limited flat land has encouraged construction along rivers such as the Guadalupe. Jim Blackburn, an environmental law professor at Rice University, observed that property owners and developers have historically sought to build in these areas. Regulations restricting floodplain construction exist in many jurisdictions, yet enforcement varies. In Harris County, Texas, more than 6,500 properties have been removed from federal floodplain maps through appeals to the Federal Emergency Management Agency, allowing owners to avoid certain building standards and insurance requirements, according to reporting by the Houston Chronicle.

At Camp Mystic, the camp had successfully petitioned FEMA to remove several buildings from the 100-year floodplain map before the 2025 flood. A subsequent Texas House investigative report concluded that the 27 deaths were preventable. The report cited the absence of an evacuation plan and delays in initiating evacuation once water levels rose. The camp’s owners had operated under the revised map for years.

FEMA is currently updating national flood maps to reflect higher observed rainfall intensities. Real estate developers have expressed concern that expanded floodplain designations could affect property values and create disclosure obligations. Blackburn noted that maps influence decisions on real estate purchases, hazardous facility siting, and hospital locations.

The federal government terminated the Building Resilient Infrastructure and Communities grant program in April 2025. The administration described the program as wasteful and politicized; it had been scheduled to distribute $882 million for projects including stormwater upgrades. A federal judge later ordered restoration of the funding. FEMA’s current website highlights a separate $600 million allocation for flood-risk reduction efforts.

Some municipalities have pursued “sponge city” designs that convert impervious surfaces to permeable materials and create retention areas such as parks. These measures aim to reduce runoff volumes during intense storms. Implementation remains uneven across regions.

In Missouri this month, flash flooding at a summer camp prompted helicopter evacuation of more than 200 children and staff. One resident, Faith Gregory, died when floodwaters swept away her home. Texas Governor Greg Abbott reported two deaths and more than 70 rescues during recent flash flood emergencies in two counties, including the county containing Camp Mystic. He stated that the fatalities did not involve campers.

The Texas Republican Party’s 2024 platform does not contain the language previously attributed to it regarding climate change initiatives. The platform does express opposition to environmental regulations viewed as obstructing business activity or private property rights.

Officials continue to issue flash flood warnings and evacuation orders during active events while longer-term infrastructure and mapping updates proceed.