File:Alamo Fire, southern California (MODIS 2017-07-18).jpg

English: In July 2017, sweltering temperatures and strong winds fueled intense wildfires in southern California. The fires forced thousands of people to flee their homes, charred dozens of structures, closed roads, and darkened skies throughout the region. One of the most aggressive fires to ignite in early July was the Alamo Fire, which was first reported on July 6.

On July 8, 2017, the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite captured this true-color image of smoke streaming from the Alamo fire. Actively burning areas, detected by MODIS’s thermal bands, are outlined in red.

Countervailing winds at different levels of the atmosphere pushed smoke plumes from the Alamo fire in opposing directions. Surface level winds were blowing out of the northwest and mid-level winds were out the southwest on July 8. As the fire grew in intensity, more smoke billowed higher into the atmosphere, where the mid-levels winds began to push it northward. The University of Wisconsin-Madison CIMSS satellite blog has posted a clip from the GOES-16 satellite showing this process unfolding throughout the day.

Surface features like buildings, trees, and mountains create friction and turbulence that contribute to differences in wind speeds at the surface and higher levels of the atmosphere.

On July 16, CAL FIRE reported that the Alamo Fire had reached 98 percent containment, after burning 28,687 acres in San Luis Obispo County near Twitchell Reservoir. One home was destroyed and another structure was damaged. The cause of the fire is unknown.