United States heat wave threatens millions with lethal temperatures

A severe heat wave is gripping the United States, with the East and West coasts both experiencing record‑high temperatures. In major cities such as Washington, DC, Philadelphia, New York, and throughout California, daytime highs are projected 10‑15 °F above normal, with inland areas of northern California reaching up to 110 °F. A lack of overnight cooling means night‑time lows remain in the 70s, intensifying the risk of heat‑related illness.

The National Weather Service has issued extreme heat warnings for the Sacramento Valley, Shasta County and surrounding foothills, labeling the threat a “Major Heat Risk.” Similar warnings cover the Portland‑Vancouver corridor, where highs of 95‑100 °F are expected. Authorities advise staying indoors in air‑conditioned spaces, drinking water, limiting outdoor activity, and checking on vulnerable neighbors. Cooling centers are being opened in California to help those without home cooling.

Alongside the heat, the storm system has produced intense thunderstorms, strong gusts, and localized flooding on the East Coast, affecting more than 70 million people and causing power outages in Pennsylvania and other states. The combined heat and storm conditions have heightened concerns about heat‑stroke, dehydration, and secondary hazards such as cold‑water shock in rivers and “king tides” on Southern California’s coast.