A haze visible in parts of the Sacramento Valley is from multiple wildfires burning in Northern California. A north wind is pushing the smoke to the valley, and a high-pressure system is locking it in with little wind.

Air quality is unhealthier-than-average for some people Thursday as winds are blowing wildfire smoke across the Northern California region.

The National Weather Service in Reno said the smoke is being driven by a slow-moving northerly flow aloft and is expected to linger through the day. Satellite imagery Thursday morning showed thick plumes stretching across northwest Nevada and the Sierra.