If you smell or see smoke at the trail head:
DO NOT hike or trail run.
DO NOT ride your horses.
DO NOT walk your dogs.
DO NOT go outside unless you must, and with a good medical grade mask on to filter out the dangerous particles that will harm your lungs.
Go here to see the current smoke map:
https://fire.airnow.gov/?lat=39.38524000000007&lng=-120.52557999999999&zoom=12