Gusting winds and dry air forecast for Thursday could drive the next wave of devastating wildfires that are already well on their way to becoming the deadliest and most destructive in California history.

Winds up to 45 mph were expected to pummel areas north of San Francisco, where at least 23 people have died and at least 3,500 homes and businesses have been destroyed. These conditions could erase modest gains made by firefighters.

Entire cities had evacuated in anticipation of the next round of flames, their streets empty, the only motion coming from ashes falling like snowflakes.

In Calistoga, a historic resort town known for wine tastings and hot springs, 5,300 people were under evacuation orders. Tens of thousands more have been driven from their homes by the flames. A few left behind cookies for firefighters and signs reading, "Please save our home!"

The 22 fires, many out of control, spanned more than 265 square miles (686 square kilometers) as the inferno entered its fourth day.  

With files from the Associated Press

With guest host Libby Denkmann.  

Guest:

Josh Rubenstein, public information officer, Cal Fire