Media playback is unsupported on your device Media caption The huge fire in Blaenau Ffestiniog was described as "looking like a volcano"

Families in about 20 homes had to be evacuated after a large fire engulfed a mountain in Snowdonia.

About 30 firefighters were tackling the blaze at Blaenau Ffestiniog, Gwynedd, at its overnight peak.

Eyewitness Chris McPhail said: "As I was driving up I could just see the glow and a load of smoke. It just looked like a volcano."

The alarm was raised just before 20:30 BST on Monday, with residents asked to leave in the early hours of Tuesday.

North Wales Fire and Rescue Service said it was still dealing with hotspots flaring up in the area and crews remain at the scene - but say there is no immediate danger to residents.

Most residents have returned to their homes but locals are offering their spare rooms to any families still displaced by the fire.

Part of the A470 - the main route between north and south Wales - through the town was shut for several hours at Church Street but has now reopened.

BBC Wales' Laura Raymond said she was woken by firefighters "smashing open" fire hydrants at about 03:00.

"The hill was literally glowing from behind," she said.

Image copyright Chris Wilson Image caption The alarm was raised just before 20:30 on Easter Monday

Image caption Fire crews spent the entire night tackling the blaze

The blaze is thought to have started behind quarry workings in an area overlooking the town called Garreg Ddu - Black Rock.

"Black Rock is like a huge gigantic lump of coal, with burning embers," said Ms Raymond.

But investigators will only start looking into what caused the fire when it is completely out.

"We've been well looked after and the crews have done an amazing job. We're just so thankful because the crews have directed it away from the houses."

Image caption The cause of the fire is not yet known

Geraint Hughes, who is managing the fire operation on the ground, said his teams had faced substantial challenges tackling the blaze.

"The rugged terrain and the steepness of it makes it difficult to put staff and personnel on the mountain to tackle it with beaters or hose-reels," he said.

He said fire crews were "currently managing" the situation, however some areas were continuing to flare-up.

Image caption The quarrying terrain has posed challenges to firefighters, says Geraint Hughes from North Wales Fire and Rescue

Image caption Garreg Ddu - Black Rock - was 'like a volcano' say eyewitnesses

Many of the evacuated residents spent the night in a cafe, including Jackie Brunger.

She told BBC Radio Wales' Good Morning Wales she was unaware of the blaze until fire crews arrived.

"It was just glowing orange and it was absolutely frightening - I've never seen anything like it," she said.

Image caption Crews from Bangor used their aerial platform to douse flames

Image caption Still burning - crews have spent Tuesday damping down hotspots above the town

"We were told to get away as soon as we could, so we took our car and went to the cafe.

"There was ash and bits of flame coming down. How far it has spread, so quickly - it was frightening."

Image copyright @mrmceej Image caption Residents say the town was under a cloud of acrid smoke

Image copyright @mrmceej Image caption Resident Jackie Brunger said one firefighter climbed the hillside directly behind her home

Sue Roberts opened up De Niros cafe for those told to leave their homes, and helped keep fire crews and police teams fed during the night.

"It's been a bit busy," she joked. "It looked quite spectacular when you think about it."