Locals on alert as bushfire at Herdsman Lake causes heavy smoke in Glendalough, Osborne Park and Wembley

A spotter plane will be back in the air over Herdsman Lake on Tuesday to look for hot spots left by a big blaze that ripped through the regional park in Perth’s north.

The lake itself acted to contain the flames that burned across the centre island of the lake while firefighters did their best to bring the situation under control.

More than 19.5ha was burnt before an afternoon wind change turned the fire back on itself, making the task easier for fire crews.

At its peak, ash from the fire was carried on the wind and spread throughout the nearby Osborne Park business district, leading to fears and an alert about the risk of falling embers.

It’s unknown what caused the blaze but the Department of Fire and Emergency Services says the circumstances appear suspicious.