ZAMA CITY, Alta. - Firefighters from Alaska and Ontario are arriving in northern Alberta to help fight a forest fire threatening Zama City.

Wildfire information officer Heather Hawkins says the crews will join more than 300 firefighters who have taken shifts battling the blaze 12 kilometres northeast of the hamlet.

About 160 residents were forced to leave last week and remain in hotels in High Level, Alta..

Another 300 people from the nearby Dene Tha' First Nation registered for voluntary evacuation due to smoke in the area.

Hawkins says a shift in the hot, dry weather may soon help battle the blaze, as rain is expected and more is forecast for Wednesday.

She says the fire was sparked by lightning, the cause of half of summer wildfires.