A large woodland and grass fire tackled overnight was probably caused by a disposable barbecue, the fire service has said.
Dozens of firefighters were called to the wildfire at Hacked Way Lane, near Macclesfield, Cheshire, just after 16:00 BST on Tuesday.
Ten fire engines and specialist units were there at its height with United Utilities helping with water drops by helicopter.
Cheshire Fire and Rescue service said a discarded barbecue was the “probable cause” and crews were still at the scene on Wednesday morning.
It was a reminder of the “devastating impact that careless behaviour can have on our countryside, particularly during periods of warm, dry weather”, they said.
The fire service urged people to stay away from the area, saying visitors continued to arrive while emergency crews worked nearby.
It said conditions could change rapidly and warned of heavy smoke, with people advised to keep their windows and doors closed and drivers were asked not to block routes needed by emergency vehicles.
Firefighters were using specialist wildfire equipment, dividing the incident into sectors, as they tried to prevent the flames from spreading.
The fire service said it would provide more updates throughout Wednesday.