Wildfire fighters in B.C. are working the province's first major blaze of the 2011 fire season.

A nine-square kilometre blaze was sparked by lightning yesterday near Tisigar Lake in northern B.C., 35 kilometres south of the Yukon border.

The aggressive fire exploded as it was fanned by high winds -- and similar conditions are expected today.

Although no homes or communities are threatened, the flames have forced closure of Highway 37 in both directions, 25 kilometres north of Good Hope Lake.