More than 20 states reported temperatures above 100F as heat dome sits over eastern US during holiday weekend

At least about two dozen people have died amid the perilous climate crisis-driven heatwave that has scorched swaths of the US with record temperatures.

As a huge heat dome sits over the county’s eastern half, extreme heat gripped millions of people in the days leading up to the US’s semiquincentennial on Saturday – and beyond it. More than 20 states experienced have reported stifling temperatures more than 100F (38C), marring celebrations. And more than 140 million people remained under active heat alerts across the US on Sunday.