Firefighters in California face critical fire threat as they work to contain several large blazes

Northern California is bracing for critical fire weather conditions as firefighters struggle to contain at least 10 large wildfires burning across the state.

A level two of three critical risk for fire weather is in effect through Monday night for a large portion of California, stretching from Redding to the region just north of Sacramento, the National Weather Service's Storm Prediction Center said.

"Fire weather conditions should continue to worsen through the morning with critical conditions quickly developing as sustained surface winds in excess of 20 mph (gusts generally 20-35 mph) overlap (relative humidity) values less than 15%," the prediction center said.