By Adrees Latif and Stephen Lam
Sept 29 (Reuters) - Firefighters on Tuesday were battling two Northern California wildfires that have already killed three people, torched wineries and forced tens of thousands to evacuate, with hot, dry conditions expected to hamper efforts to control the blazes.
The three fatalities in the so-called Zogg Fire in Shasta County about 200 miles north of San Francisco were reported by the county sheriff. They were all civilians.
The deaths brought to 29 the number of people killed since mid-August in California's worst wildfire year on record in terms of acreage burned.
"With no significant precipitation in sight, California remains dry and ripe for wildfires," the state's wildfire agency Cal Fire said in a Tuesday statement.
The Zogg fire, which has destroyed 146 structures and charred 40,317 acres of grassy hillsides and oak woodlands, coincided with another wildfire in the heart of California's wine country north of the Bay area.
That blaze, dubbed the Glass Fire, has spread across 36,000 acres of similar terrain in Napa and Sonoma counties, incinerating more than 100 homes and other buildings, according to CalFire.
Governor Gavin Newsom declared a state of emergency in the three counties.
The fires marked the latest flashpoints in a destructive spate of wildfires this summer across the Western United States.
California fires have scorched over 3.8 million acres (1.5 million hectares) since January - far exceeding any single year in state history. They have been stoked by prolonged bouts of heat and dry-lightning sieges that scientists attribute to climate change.
More than 7,000 homes and other structures have burned statewide this year.
The Glass Fire in the Napa Valley forced the evacuation of Calistoga, with over 5,300 residents, and merged with two other blazes in western Napa County and Sonoma County.
An estimated 60,000 residents are under evacuation orders or advisories in Sonoma and Napa counties combined, but no injuries have been reported.
Red-flag warnings for extreme wildfire risk were posted for much of Northern California. (Reporting by Adrees Latif and Stephen Lam; Writing by Andrew Hay; Editing by David Gregorio)
