An out-of-control wildfire east of Skaha Lake in the Okanagan has grown from 20 to 500 hectares.

The Regional District of Okanagan-Similkameen issued an evacuation order for 77 properties in Electoral Area D. Another 600 properties are on evacuation alert.

The Thompson Creek wildfire was discovered on Sunday (July 11).

Skaha Lake is 11.3 kilometres south of Penticton.

Another out-of-control wildfire seven kilometres west of Sun Peaks is 290 hectares. It's now being called the Embleton Mountain wildfire to reflect its geographic location.

The Thompson-Nicola Regional District has issued an evacuation order and expanded its alert for Electoral Area P (Rivers and the Peaks).

This fire was discovered on July 8.

In addition, Sun Peaks Mountain Resort Municipality has issued an evacuation alert for all properties within its boundaries. There are about 790 permanent residents in the municipality, according to its website.

The B.C. Wildfire Service has issued two warnings in connection with people using drones near wildfires. The most recent occurred on July 11 when air operations had be halted on the Kimbol Lake wildfire near Nakusp.

It's illegal to use a drone near an active wildfire because unmanned aerial vehicles can have deadly consequences if they collide with firefighting aircraft.

"Anyone caught operating a drone that interferes with fire control could be fined up to $100,000, or jailed for up to one year, or both," the B.C. Wildfire Service states on its website.

There are 306 active wildfires across B.C., which is up by 35 over the last two days.

Meanwhile, Environment Canada has issued a heat warning for parts of the B.C. Interior dealing with some of the worst interface wildfires, with daytime highs expected to reach 35 to 38 C.

The warning applies to the South Thompson, Fraser Canyon, South Okanagan (including Penticton), and Boundary regions.

Temperatures are expected to remain this high through Wednesday (July 14).