Les cartes montrent des menaces de chaleur extrême et d'inondation à travers les États-Unis.

Maps show extreme heat and flood threats across U.S. A massive heatwave continues to grip large portions of the United States, with dangerously high temperatures persisting in the desert Southwest and extending northward into the northern tier of the country. At the same time, severe storms are expected to sweep across parts of the South, bringing heavy rain and raising flood concerns. These dual threats have prompted widespread warnings and preparations across the nation. The National Weather Service issued extreme heat warnings and advisories for regions spanning from Montana and the Dakotas through Minnesota, Wisconsin, Michigan, and into the Northeast. These areas collectively house over 130 million residents, many of whom face heightened risks due to prolonged exposure to dangerous heat levels. The heat index, factoring both temperature and humidity, is projected to peak in the northern Plains on Tuesday, reaching approximately 110 degrees Fahrenheit. This level of heat poses serious health risks, particularly for vulnerable populations such as the elderly and those with preexisting medical conditions. Meteorologist Nikki Nolan of CBS News noted that temperatures in these regions are expected to be 20 to 30 degrees above seasonal averages. Some locations could surpass 100 degrees, with specific records being challenged or broken. For instance, Fargo, North Dakota, might hit 99 degrees on Tuesday, which would approach a daily record established in 1936. Similarly, Rapid City, South Dakota, could reach 105 degrees, surpassing a previous record set in 2012. In Syracuse, New York, temperatures may climb to 97 degrees, marking the city’s hottest July 14 since the 1950s. While the Northeast braces for the height of the heatwave, the West remains under similar stress. High temperatures in California continue to fuel wildfire dangers and exacerbate public health concerns. Extreme heat warnings and advisories cover a wide swath from San Francisco to Los Angeles, with triple-digit readings anticipated in Southern California. Unlike other regions, nighttime temperatures in the area may not offer much respite, as lows could reach unprecedented highs. Meanwhile, in the South, a stationary weather pattern has triggered multiple rounds of heavy rain and thunderstorms, prompting flood alerts for nearly 20 million people in Texas. The focus of concern lies in the Texas Hill Country, which suffered catastrophic flooding during the deadly July 2024 floods. The region is once again facing elevated flood risks, with the National Weather Service warning of potential flash flooding due to intense rainfall rates exceeding two inches per hour. Areas experiencing the heaviest downpours could receive between 10 and 15 inches of rain, while broader regions might see 4 to 6 inches. Houston and San Antonio, among other major metropolitan areas, are also under watch for possible impacts from the storm system. Emergency officials are urging residents to prepare for sudden changes in weather and to monitor updates from local authorities. With both heat and flood threats active across different parts of the country, the coming days will test the resilience of communities and infrastructure alike.