The Wildfire Management Branch says firefighters have contained about 25 per cent of the blaze about 67 kilometres west of Pemberton, B.C.
Cooler and wetter weather has helped, but crews may be challenged by hot and dry conditions expected next week, says the branch.
"This fire is in very steep and inaccessible terrain, in thick forest," says a notice posted on the branch website.
"This valley, and the trees within it, are very dry and it is expected that it will not receive substantial rainfall in the foreseeable future."
It says smoke drifting into the Squamish and Pemberton valley is likely to intensify and travel long distances due to forecasted winds.
The cause of the fire is currently being investigated, but it is believed to be human-caused.
Ninety-four firefighters, six helicopters and three pieces of heavy equipment are battling the blaze.
The branch is also warning recreational boaters to avoid the waters near Mount Benson west of Nanaimo, B.C., while water-skimming aircraft fight a four hectare fire.
No structures and homes are threatened by the human-caused blaze, but it is growing quickly on felled and bucked timber on private forestry land, the branch says.
The public is being warned not to light large bonfires or "party fires," to extinguish cigarettes in water and avoid driving or parking in tall grasses.
Thirteen firefighters, two helicopters and air tankers are responding to the blaze.