Western Australian Department of Fire and Emergency Services Commissioner Darren Klemm said the loss of 86 homes was an "absolutely devastating outcome".
Klemm praised firefighters working in challenging conditions overnight, but warned strong winds still posed a risk for communities with emergency warnings still in place in several areas.
"We've experienced once again some incredibly challenging conditions overnight for firefighters with incredibly strong winds and those winds have continued into today," he said. "The weather today is slightly cooler, but we have still got the strong winds today and, again, tonight, ahead of hopefully a forecast change with some possibility of rain later on Saturday afternoon."
No deaths have been reported from the fires, the origins of which are still unknown, although the blazes are a reminder of the scores of fires that razed large swathes of Australia's east coast last year.