The small Sierra town of Greenville, Calif., was heavily damaged on Wednesday night into early Thursday as the Dixie Fire surged northward amid high winds, extremely dry air and hot temperatures.

The big picture: The Dixie Fire, California's biggest blaze and the sixth-largest wildfire in state history, razed houses and businesses as it ripped through Greenville and surrounding areas in Plumas County.

• Authorities issued mandatory evacuation orders for Greenville, about 240 miles northeast of San Francisco, and other communities as the blaze moved in.
• “If you are still in the Greenville area, you are in imminent danger and you MUST leave now!!” the Plumas County Sherrif's Office posted on Facebook.
• According to the AP, the blaze gutted downtown buildings dating back a century or more. “We did everything we could,” fire spokesman Mitch Matlow told the news service. “Sometimes it’s just not enough.”

Threat level: Firefighters are facing the challenge of extremely dry air, hot temperatures and high winds, which have prompted the issuance of Red Flag fire weather warnings through Thursday evening.

• Such conditions are likely to lead to additional extreme wildfire behavior, including the rapid and erratic movement of the blaze and formation of towering pyrocumulus clouds above the fire.

Zooming-in on the Dixie Fire.

A hi-res view of its several pyrocumulus plumes. pic.twitter.com/lVK0LSLVdD

— Dakota Smith (@weatherdak) August 5, 2021

By the numbers: In addition to the Dixie Fire, multiple other wildfires are burning in northern California as well. As of Wednesday evening, the River Fire had burned 1,400 acres and was 0% contained.

• The Dixie Fire is now the 6th-largest blaze in California history by acres burned, at more than 320,000 acres so far. That's up more than 50,000 acres in size compared to Wednesday.
• Illustrating the dangerous conditions in place, the River Fire exploded from a spark on Wednesday to well over 2,000 acres by dusk and growing quickly, threatening several small towns, and billowing smoke more than 30,000 feet into the sky.

Context: The extremely dry conditions in northern California are the result of a severe drought, which is the worst the West has seen so far this century.

• Northern California as well as the neighboring states of Oregon and Washington have also experienced repetitive heat waves this summer that have dried out the forests even more, and shrunk lakes and reservoirs to record low levels.
• Human-caused climate change is driving an increase in the likelihood and severity of heat waves and droughts, and is behind a trend toward larger wildfires in much of the West in recent years, studies show.
• Last year was California's worst wildfire season on record. So far, this season is ahead of last year's pace, and the climatological peak of the season doesn't begin for several more weeks.

Rebecca Falconer and Jacob Knutson contributed reporting.