You can expect smoke in the valley up to Lake Tahoe today… and in some areas conditions are hazardous.
If you can see or smell smoke, officials say, you should avoid outdoor activities.
Wildfire smoke contains toxic gases, and fine particles that are associated with various health problems.
Wearing bandanas or paper masks do not protect you from the air particles, and can even impede breathing.
Smoke is more concentrated in the foothill regions during cooler, mornings. In the afternoon and evening, smoke rises and may affect the Lake Tahoe region.
Wind directions are expected to change this weekend. That could improve smoke conditions in some areas.