Fire crews prepare for difficult day in B.C.

Firefighters in British Columbia's southern Okanagan are bracing for a change in wind and weather that has the potential to drive a huge wildfire north toward the outskirts of Penticton.

Calm winds over the last few days are forecast to switch direction and gain strength over the 20-square kilometre wildfire that has already destroyed one home and forced hundreds of evacuations.

The BC Wildfire Service says it is increasing the number of teams capable of setting up sprinkler systems to protect more of the roughly 3,700 homes lying in the possible path of the fire.

Residents of those properties have already been warned to be ready to leave and they've been urged to pre-register with emergency services so officials can prepare for them.

In southeastern B.C., a four-square kilometre wildfire burning west of Canal Flats has exploded to 30-square kilometres in size, but it's not immediately threatening more properties, with just 10 on evacuation order.

And residents of a development on Lillooet Lake, north of Vancouver, have been ordered out because heavy rain, coupled with a wildfire on the steep hills above their properties, has the potential to cause a damaging debris flow or cut the only road to the area.

The evacuation order from the Squamish-Lillooet Regional District says there is an "imminent risk" that burned trees and other debris could sweep down McCullock Creek or Catiline Creek just east of Pemberton.

Downpours affecting the Pemberton area are also forecast to drench much of B.C.'s lower south coast, including Vancouver, and Environment Canada has posted rainfall warnings for Howe Sound and the extreme northeast corner of the B.C.

The weather office has also issued severe thunderstorm watches for central and northeastern sections of the province.

Forecasters are calling for strong wind gusts, large hail and heavy rain, and say the storm is also expected to pack lightning.

However, the wildfire service website shows the risk of forest fires through the Cariboo, Prince George, Stuart-Nechako and Peace River areas is ranked no higher than moderate.