Ten fire engines are currently battling a caravan fire which threatens to destroy an adjacent thatched property.
The fire service was called just after 12pm to a fire involving a caravan on the A357 by the Glue Hill Junction near Sturminster Newton.
The caravan is believed to contain gas cylinders.
Fire engines and from Sherborne, Sturminster Newton, Wincanton, Shaftesbury, Gillingham, Blandford and an aerial appliance from Yeovil were all sent to the scene to try to bring the fire under control.
The fire is now known to have started in the caravan, which has been destroyed, but the cause of the fire is not known.
The blaze quickly spread to a nearby tree which in turn set fire to the corner of a thatch roof on an adjacent property.
A spokesman from Dorset and Wiltshire Fire and Rescue said: "We have surrounded the fire and are currently doing a lot of protection work with both water and foam to the thatched property to try and prevent it catching.
"What we don't know is whether the fire has already got underneath so at the moment we are treating it as a thatch fire and trying to stop it in its tracks."
Officers are currently assisting the fire service at the scene of a caravan fire near the Glue Hill junction on the A357 near Sturminster Newton. A road closure has been put in place on the A357 between the B3092 Bridge Street and Glue Hill. Motorists are urged to avoid the area.
— Dorset Police (@dorsetpolice) November 16, 2018
Police are also on the scene and have shut the A357 in both directions to allow the fire service to carry out their work.
Access to and from Glue Hill is also restricted.
Traffic is queueing on the B3092 Bridge Street between B3091 Old Market Hill and A357 Newton Hill.
The road closures are also causing delays through Sturminster Newton.
Update:
Fire crews managed to bring the fire under control and they are began to scale down the operation around 3pm.
A spokesman for DWFRS said crews had to cut in a 'thatch break' into the roof.
"We are cutting into the thatch from the gable end and stripping the thatch back to ensure there is no smouldering or sign of fire underneath.
"The problem with thatch is it can burn from inside so you can't see it. We've worked hard to stop the spread and although there is damage to the roof it could have been a lot worse," she said.
The spokesman added the fire service would aim to clear the road as quickly as possible.
The road was reopened just after 4.30pm.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here