Torrential rain and flooding disrupt Memorial Day travel across the U.S.

Torrential rain turned the Memorial Day rush into a weather emergency for millions, with airport delays, flooded roads and last-minute route changes complicating one of the busiest travel periods of the year. AAA said 45 million Americans were expected to travel 50 miles or more from May 21 through May 25, a level that could make the holiday the busiest ever for travel.

The disruption was already showing up in the nation’s airports. More than 1,000 flights were delayed and nearly 290 were canceled within, into or out of the United States on the morning of May 21, according to NBC News citing FlightAware. The Federal Aviation Administration also issued a ground stop at Chicago O’Hare International Airport because of thunderstorms, a sign that the storm system was not just a local nuisance but a broader transportation problem hitting a major hub.

The worst flooding concerns stretched across a wide swath of the country. Flood watches were in effect in parts of southern and southeast Texas, including Galveston and Corpus Christi, where rainfall rates of 2 to 4 inches per hour were possible. NBC News identified Oklahoma City, Tulsa, Houston, Shreveport and Lake Charles as cities that could face flash flooding through the weekend, while ABC News said a widespread 1 to 2 inches of additional rain was likely from southern Louisiana up to the Carolinas, with pockets of 2 to 4-plus inches possible.

The National Weather Service warned that floods are the most common and widespread weather-related natural disaster and that flash floods can develop within minutes. It also says flooding occurs in every U.S. state and territory, a warning made more urgent by the kind of conditions that can turn low-water crossings, underpasses and riverbanks into traps in a matter of moments.

That danger became real in West Virginia, where 28 Boy Scouts from Fairfax County, Virginia, were rescued after becoming trapped along the Cacapon River in Hampshire County. The incident underscored how quickly a holiday outing can turn into an emergency when river levels rise and access routes vanish.

The storm system also threatened major events beyond travel. ABC News said the forecast could affect the 110th Indianapolis 500, while the continued wet pattern kept pressure on roads, airports and local responders across the eastern half of the country. With rain still pressing from Texas to the Carolinas, the holiday weekend became a test of how well transportation agencies and emergency crews could keep up as conditions changed by the hour.