British Columbia's wildfire service says this week will bring "increased heat," marking a 15-day trend of hot and dry weather that has fuelled a surge in fire activity.

A provincial fire situation report says there's potential for thunderstorms in the Interior, while the northeast returns to a warming trend after a three-day break.

Environment Canada maintains heat warnings for parts of the southern Interior from the Fraser Canyon up to the south Cariboo as well as the Okanagan Valley, communities along the Canada-U.S. border and the Kootenay Lake area.

The weather office says daytime highs in the 30s are expected through the week.

The BC Wildfire Service says the northwestern part of the province continues to experience a reprieve from the heat with rain showers in the forecast.

The number of active wildfires continues to hover at about 150, including a one-hectare blaze the service says is "highly visible" from the Trans-Canada Highway between Chilliwack and Hope.

B.C.'s driver information service DriveBC says one eastbound lane is closed.

The wildfire service says the blaze is about one hectare in size and two initial attack crews and a helicopter from the provincial service are assisting the local fire department.