The dry spell was accompanied by sweltering temperatures across much of the U.K., following heat waves in May and June. Rising temperatures and prolonged drought leave vegetation drier and more combustible, allowing fires to spread faster and burn more intensely. The wildfire burned about 420 square kilometers (162 square miles), making it France’s largest wildfire on record. About 1,500 firefighters, supported by water-dropping helicopters, continued reinforcing fire lines along the blaze that tore through about 18 square kilometers (7 square miles). The Dutch air force sent two Chinook helicopters equipped with large water containers to help firefighters tackle the blaze.