The Woodhead Pass is shut in both directions after a lorry carrying wood chippings set alight.
Emergency services were called to the blaze at around 3.30am this morning.
The road is shut in both directions from Market Street, in Hyde, outside the Gun Inn.
Drivers are being advised to avoid the area and find alternative routes.
South Yorkshire Police have said the lorry is still smouldering and it may have damaged the carriageway.
This is due to the wood chippings it is carrying prolonging the fire.
Highways England said the fire is out, but work to clear the carriageway is expected to take some time.
A statement said: "Emergency services are working at the scene with recovery expected on scene shortly to remove the vehicle and clear the carriageway of debris.
"This is expected to be ongoing during the morning rush and traffic is advised to allow additional time or consider alternative routes where possible.
"Traffic is being diverted locally around the incident."
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