Police and fire officials in New Jersey are warning residents that low-hanging wildfire smoke is setting off carbon monoxide detectors Sunday morning.

Wildfires were burning from one end of New Jersey to the other on Friday after one of the driest months on record, leading New York City to issue smoke warnings and forcing farmers to take steps to protect their harvests.

After forcing thousands of Californians to evacuate and burning more than 100 structures, a stubborn wildfire burning northwest of Los Angeles on Friday challenged firefighting crews working to snuff it out even as fierce winds in the area calmed.