(NBC News)  Evacuations continue as a string of wildfires burning across Northern California continue to grow.

At least 17 people have been killed by fires.  Close to 200 more have been injured, and more than 100 others are missing.

Officials estimate that more than 3,500 homes and commercial buildings have been destroyed, and more losses are expected.

"Yesterday was an aggressive day for fire behavior," Napa County Fire Chief Barry Biermann said Wednesday morning. "We are expecting some extreme fire behavior and growth of our incidents." 

High winds are expected to return Wednesday evening, making the job harder for crews working to contain the fires.

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