California fires: Death toll reaches 31 as firefighters continue to battle blaze

The most lethal wildfire event in California’s history has killed people as they slept in their beds and prompted authorities to evacuate thousands of residents from the region.

The toll from the more than 20 fires raging across eight counties is likely to climb, with more than 400 people listed as missing in Sonoma County alone.

Winds of up to 60mph (100kph) and humidity of just 10 per cent will create “critical fire weather conditions” and “contribute to extreme fire behaviour” into the weekend, the National Weather Service said.

A force of 8,000 firefighters is working to reinforce and extend buffer lines across the region where the flames have scorched more than 190,000 acres (77,000 hectares), an area nearly the size of New York City.

With 3,500 homes and businesses incinerated, the so-called North Bay fires have reduced whole neighbourhoods of Santa Rosa city to smoldering ruins dotted with charred trees and burned-out cars.

The cause of the disaster is under investigation, but officials said power lines toppled by gale-force winds last week may have sparked it.

As many as 900 missing-person reports have been filed in Sonoma County but 437 have since turned up safe.

It remains unclear how many of the 463 still unaccounted for are victims rather than evacuees who failed to alert authorities.

The fires struck the heart of the world-renowned wine-producing region, wreaking havoc on its tourist industry and damaging or destroying at least 13 Napa Valley wineries.

California’s newly legalized marijuana industry also was hit hard, with at least 20 cannabis farms in Sonoma, Mendocino and Napa counties ravaged, said Hezekiah Allen of the California Growers Association.