A smoke advisory issued because of the Morgan Fire on Mount Diablo has prompted schools and other community services in the area to keep activities indoors.
The Morgan Fire, which started Sunday on Morgan Territory Road near Mount Diablo State Park, southeast of Clayton, has spread to more than 3,700 acres.
As of Monday night it was about 20 percent contained, according to Cal Fire officials. As many as 100 homes are threatened and evacuations have been ordered.
The Bay Area Air Quality Management District issued a smoke advisory Monday because of the blaze. The smoke may affect residents in parts of Contra Costa, Alameda and Santa Clara counties, according to the air district.
In Danville, people living at the base of the mountain are putting family pictures and valuables in one place, just in case they have to get out quickly.
Parked cars in town had a layer of ash on them Monday. Resident Sandi Smith said it looked like snow at lunch.
"Stopped and had lunch outside and little flakes were falling on my black pants," she said.
Danville city officials announced that outdoor classes and sporting activities would be canceled because of smoky conditions.
Baseball, tennis, softball and bocce ball adult and children's leagues were notified about cancellations, affecting some activities planned for Monday afternoon.
Teen Centers throughout Danville will remain open, however all activities will be kept inside.
City officials encouraged all residents to limit time spent outside as the fire continues to burn.
At the Clayton Library the Red Cross set up an evacuation center and shelter, which was used by three people Sunday night.
On Monday night it was just Scott Arnott using the evacuation center. He said a park ranger told him to evacuate the Curry Creek RV park fast.
"Very scary everything you've worked for all your life could go up in flames." Arnott said.
He is hoping crews get the upper hand and have some good news for him Tuesday. The shelter will remain open as long as there is a need, officials said.
Meanwhile, the Dublin Unified School District notified parents Monday that because of the polluted air from the wildfire, district schools, including Dublin High School, are instituting "rainy day" procedures.
That means that students will not go outside for recess, physical education classes or lunchtime, school officials posted on the district's Facebook page Monday afternoon.
The air district has advised all residents in smoky areas to stay inside, close windows and doors and set air-conditioning units and ventilation systems to re-circulate indoor air.
More information about air quality is available at www.baaqmd.gov.