the boulder fire was reported at 10:49 am on boulder creek trail in california valley, california on june 5, 2019. the fire, fueled by grass, had grown to acres by the time it was reported. by noon, the fire had grown to . within a half an hour, 40 percent of it had been contained and one building and a solar array were under threat. the fire's smoke, which was very dark, was visible in eastern san luis obispo. air tankers were assigned to fight the fire later in the day. the fire was contained by the evening of june 5. it had burned a total of .