Firefighters are tackling an enormous blaze that broke out on Saddleworth Moor between Manchester and Huddersfield.
Crews have been at the scene at Marsden Moor since it started at around 7.30pm on Tuesday.
More than 30 firefighters from West Yorkshire and Greater Manchester fire stations were deployed and police were forced to close the A62 between the Colne Valley and Diggle in both directions to protect the public.
Dramatic photographs have been shared on social media of the fire, which turned the night sky orange.
The blaze erupted on National Trust property near Marsden and covered about one-and-a-half square kilometres of land at its peak, with firefighters having worked through the night to try to extinguish it.
West Yorkshire Fire and Rescue Service station commander Laura Boocock told the Manchester Evening News that she would make a decision on whether helicopters need to be deployed to help at sunrise.
The newspaper reported that the fire broke out near an old pub, which is not thought to be at risk.
One witness described the blaze as an “apocalyptic scene”, which some have said is reminiscent of the “unprecedented” blaze that spread across the moor last summer.
The army was scrambled to help police and firefighters cope with those flames, which took three weeks to be completely extinguished amid a scorching heatwave.
Britain has basked in unusually warm February temperatures over the last two days, but neither Greater Manchester Police nor the local fire and rescue service have commented on what the cause of the latest blaze might be.
Temperatures in Manchester clocked in at an unseasonable 19C (66F) on Tuesday and it is forecast to be dry and sunny again on Wednesday, albeit slightly cooler.
Green Party deputy leader Amelia Womack tweeted: “It’s February! Our countryside shouldn’t be a tinderbox!”
One witness, John Turner, told Sky News: “There were lines of flames, like someone had put down petrol on the hillside and it was just a massive ring that went zigzagging up and down the hill and all around in a circle.
“It’s like the sky is on fire, almost.
“There was a group on the hill, just pulled over, and there were people saying ‘it looks like the end of the world, it looks like the apocalypse is happening’.”
The dramatic scenes, which could be seen from miles away, come just a week after fire crews had to put out another blaze on the moor.
Greater Manchester Fire And Rescue Service spent two hours tackling the flames last Monday evening, and a cause was not established.
Elsewhere on Tuesday evening, a sizeable gorse fire broke out on Arthur’s Seat in Edinburgh.
The fire on the Salisbury Crags covered about 800 square metres of land and police were forced to close Queen’s Drive between Dynamic Earth and the Commonwealth Pool after the alarm was raised.
No injuries have been reported at Marsden or Arthur’s Seat.