Winds force Sydney Airport to close runways and cancel flights, a day after a dust storm shrouded the Australian city.

Strong winds across Australia’s southeast coast on Friday caused chaos at Sydney and Melbourne airports, the country’s two busiest, with thousands of air travellers stranded as runways were closed and dozens of flights cancelled.

Winds gusting up to 70 kilometres per hour also fanned major bushfires along the east coast, forcing people to leave their homes.

Sydney Airport cancelled 76 flights after all but one of its three runways was closed due to the wind.

“It’s not safe to have flights landing or departing and as a result we are going to a single runway, there are delays,” Sydney Airport told Reuters.

Melbourne Airport also reduced the number of flights allowed to arrive and depart each hour as a result of the Sydney Airport cancellations.

The strong winds fanned fires across the state of New South Wales, with Australia’s Rural Fire Service reporting 21 fires.

A Boeing 737 modified for use as a water-bomber was used to fight bushfires around the city of Newcastle, north of Sydney, said the Rural Fire Service. The aircraft can carry 15,000 litres of water or fire retardant.

“(This) was the first operational drop that it’s done in the world…it has proven to be effective,” Chris Garlick, a spokesman for the NSW Rural Fire Services told Reuters.

Fires around the popular tourist spot of Port Stephens, nearly 200km north of Sydney, forced an emergency evacuation of residents. There were no reports of injuries or loss of property. Emergency workers warned the strong winds threaten escalate the fires.

The strong winds are part of a massive weather system over southeast Australia. On Thursday, it created a massive dust storm, which swept across the drought-parched interior and blanketed Sydney.

The Australian Bureau of Meteorology said winds should ease by Friday evening.