Exhausted fire brigades battled wildfires for a fourth straight day across southern California yesterday, as smoke and flames forced an estimated 1m people to flee their homes. Financial Times

By yesterday morning, more than a dozen fires had hit an estimated 645 sq miles – an area larger than Greater London – killing five people, destroying nearly 1,500 homes and threatening thousands more.

As the human toll of the disaster continued to mount, officials and insurers struggled to get to grips with the likely economic fallout.

San Diego county officials said the blazes had caused at least $1bn (£490m, €700m) in property damage – a figure that was likely to rise as the true economic toll of the disaster become clear. Insurers expect claims running into hundreds of millions of dollars.

Businesses along a 200-mile stretch from Santa Barbara to San Diego were forced to close their doors or scale back operations because of the flames. San Diego Gas & Electric, a power utility, said flames under its transmission lines had forced it to cut power to thousands of customers.