Fire crews mop up a fire in Kamloops on Wednesday as about 165 new fires are sparked by lightning. (CBC)

Lightning strikes caused an estimated 165 new wildfires in B.C.'s Interior overnight Wednesday, prompting officials to issue two new evacuation orders and call in aerial reinforcements as hot, dry weather continued to blanket the province.

On Wednesday, officials decided to bring in an extra air tanker from Yukon to help dump water and flame retardant on the fires as the province's fire crews had their busiest day of the season so far.

While many of the new fires burning across B.C. remain small, officials say nearly 20 notable fires pose a potential threat to the public.

Officials prioritize fires burning near homes and communities while others in remote areas are often left to burn out on their own.

Extra air tanker support

Jeff Berry, the superintendent of the provincial air tanker program based in Kamloops, says more equipment might have to be brought in from Alberta, Saskatchewan and even Alaska if the fires persist.

"We're looking at a Convair [air tanker] that's being released out of Alaska for Friday, and we're considering other options if any other aircraft come available — mutual aid — from Alberta or Saskatchewan," Berry said.

When there are this many wildfires, co-ordinating where the aircraft dump their water and flame retardant is critical, Berry said.

An air tanker plane drops a load of flame retardant on an Okanagan wildfire on July 12 in this photo submitted by a reader. Officials say they plan to call in additional air tankers to help fight the fires. (CBC)

"When we get overwhelmed, when we get this many fires, it really becomes a really key job of making sure we're winning where we can and losing where we should," he said.

The province's air tankers are land-based aircraft that must return to the base to take on additional fire retardant, and there are only so many tankers that the operational centre can handle, Berry said.

"Given the number of aircrafts we have right now, it's pretty hard to put any more in the chain … because they physically can't load at the bases," he said. "There's just only so much space. We sort of have to manage both sides of that."

Evacuations ordered

After Wednesday's rash of lightning strikes and a fire that quickly spread to cover 150 hectares, officials ordered the evacuation of about 60 homes near Bonaparte Lake, north of Kamloops.

A firefighter surveys a fire east of Kelowna on Thursday. (CBC)

An evacuation order was also issued for about 20 residents of the Riske Creek military base in the Cariboo region.

Smoke from the blaze was raising health concerns Thursday morning in nearby Williams Lake, where the air quality rating was high, meaning children and the elderly should consider reducing outdoor physical activity.

A small wildfire was also sparked in the hills above Kelowna's Joe Riche neighbourhood. Forestry crews were working their way into the area, and the size of the fire has not been determined.

Meanwhile, in B.C.'s far northwestern corner, a wildfire has caused the closure of a main highway heading into the Yukon. Highway 37 is closed from a point 30 kilometres south of the Yukon border all the way to the border crossing. The only other route into the Yukon is via the Alaska Highway, a detour of more than 1,700 kilometres.