An aggressive wildfire burning near Trail, B.C., was creeping closer to homes on Saturday, fuelled by wind and low humidity.

The South Pend d'Oreille blaze now covers at least 20 square kilometres and is moving northeast, officials said.

Smoke from the fire, sparked by lightning last Sunday, could be seen more than 200 kilometres away on the weekend.

Most of the scorched land is on the Canadian side of the border, but a few dozen hectares have burned in Washington state.

About 40 people living in the Pend d'Oreille Valley near the U.S. border remain on evacuation alert and B.C. Hydro is monitoring a dam and substation in the area.

Fanned by strong winds, the fire jumped a river on Friday night.

Ali Grieve watched from her home in nearby Fruitvale as the fire spread. She called it a "pretty spectacular display of explosive fire."

"It actually took my breath away," she told CBC News. "I could see the flames on top of the ridge. You always think your community is safe and protected. It was on the edge of our doorstep last night."

Elsewhere, rain and cooler weather will likely mean a forest fire burning near a ski resort in Kelowna will not get bigger this weekend, officials said.