A wildfire burning north of Santa Barbara on Saturday, August 20, sent huge plumes of smoke into the sky. The Rey Fire had spread over 21,000 acres as of Sunday, three days after it started in the Los Padres National Forest. This timelapse video shows pyrocumulus clouds, or fire clouds, swirling above the blaze.A pyrocumulus cloud is a dense cumuliform cloud formed by the intense heating of the air, caused by a wildfire or volcanic eruptions. Credit: YouTube/Jesse Rockwell