Heat wave disrupts Fourth of July events across US, strains power grids

A dangerous heat wave upended Fourth of July celebrations across swaths of the central and eastern U.S. on Friday, forcing officials in the nation’s capital and elsewhere to cancel or postpone dozens of parades, concerts and fireworks displays.

Among the events disrupted by the sweltering heat was the Great American State Fair on the National Mall in Washington, a centerpiece of President Donald Trump’s efforts to mark the nation’s 250th birthday....