British Columbians flocked to the beach over the weekend to beat the heat. (CBC)

Forestry officials in B.C. are searching for any new wildfires sparked overnight Sunday as a heat wave continues to blanket the province.

The hot weather smashed daily temperature records over the weekend, with Squamish hitting 36.7 C, shattering its previous record by nearly five degrees.

The heat was on across the Fraser Valley, too, with Agassiz sweltering at 34 C — another record.

On Vancouver Island, Port Alberni also set a new high Sunday — 35 C — but that's balmy when compared with the 38 C forecast for Monday up the Fraser Canyon in Lytton and Lillooet.

Temperatures across the province aren't expected to moderate until midweek, with the chance of showers in some areas — including Vancouver — by the weekend.

Evacuations expanded

The weekend heat wave is getting the blame for many of the 25 new wildfires that broke out Saturday and Sunday.

"We're really just crossing our fingers that the weather helps us out because the hot temperatures are what's making the fuel susceptible to new fire starts and making those wildfires more active," said fire information officer Alyson Couch.

In less than a week, the high or extreme wildfire danger in B.C. has spread from about one-third of the province to almost three-quarters.

There are more than 270 wildfires burning across B.C., according to fire officials, including one new fire near the community of New Aiyansh in the Nass Valley, just north of Terrace.

On Sunday, officials in the Interior issued an evacuation order for the Chisolm Lake area and expanded one for residents around fires at Tsacha Lake and Pelican Lake. They also issued an evacuation order for the Meldrum Creek area Saturday.

The Meldrum Creek wildfire, seen Aug. 3, has scorched an estimated 83 square kilometres. (B.C. Wildfire Management Branch)

"We are seeing very significant fires burning in there and they have been a challenge for our crews. But we will continue working on them, putting in some guards, and trying to eliminate some fuel so hopefully they don't have anything left to burn onto," said Couch.

Highway 37, about 80 kilometres south of the Yukon border, remains closed because of a nearby wildfire.

Campfires and open fires have already been banned across much of the province and the Lower Mainland fire hazard rating is expected to reach extreme in the coming days if cooler weather does not arrive.

If that happens, smoking and the use of charcoal barbeques in public parks and beaches will be prohibited.