Power lines, hikers, arson: What might have sparked LA's devastating fires?

The hiking trail through Temescal Canyon in western Los Angeles is a favourite of locals.

Towering above the twisting roads and manicured homes that make up the Pacific Palisades, urban hikers seeking an escape from America's famously gridlocked city have a clear view of the pristine waters of the Pacific.

Now the green, brush-lined path in the canyons is grey and burned as far as the eye can see.