A Vancouver couple have posted a terrifying video of their escape as wildfires transformed a highway into a tunnel of flames and smoke.

Sally Aitken and her husband, Jack, were staying at their summer home on Tatla Lake about 220 kilometres west of Williams Lake over the weekend.

They decided to leave after they lost power and smoke from nearby wildfires began to grow thicker.

The highway was closed when they first tried to drive out, but when it reopened to eastbound traffic on Sunday, they decided to make a move.

"We thought we'd better head out while the road was open because it wasn't clear that it would stay open," said Aitken.

'You couldn't see anything'

When they began the drive to Williams Lake late Sunday afternoon, Sally said they could see fires burning on either side of the road, but the visibility was fine.

As they continued farther east along Highway 20, the conditions worsened.

"As we drove, we entered this thick black cloud that was dark as night. You couldn't see in front of you ... you could see the line on the road and that was it," said Aitken.

"That's where the video ends, because there's nothing you could film at that point, but that continued for quite a long time and was very frightening."

Driving out of Hanceville

When the couple first set out, the fires were near but visibility was OK. (Sally Aitken/Twitter)

Aitken and her husband made it to Williams Lake safely, then later to Kamloops before returning to Vancouver.

"We've never seen anything like this, and we had no idea given that the highway was open how bad it would be once we got in there," said Aikten.

More than 14,000 people in B.C. have already been forced from their homes because of wildfires.

Other communities have been warned to be ready to leave on a moment's notice if conditions deteriorate. That includes the City of Williams Lake, where approximately 10,000 people currently live.