Planes struggle to land at Heathrow Airport as Storm Eunice hits London.

Millions of people in the U.K. were urged to cancel travel plans and stay indoors Friday as the second major storm this week prompted warnings of high winds and flying debris across northern Europe. Britain’s weather service said Storm Eunice, known as Storm Zeynep in Germany, was likely to cause significant disruption and dangerous conditions, with gusts that may exceed 90 miles per hour in highly exposed coastal areas. British Airways warned of delays at London’s Heathrow Airport because the weather has reduced the rate at which aircraft are permitted to land.