Wildfire smoke from several fires has triggered a smoke advisory for wide swaths of Southern California until Thursday evening, according to officials.

Wildfires are forcing evacuations across California, displacing thousands as conditions rapidly change and smoke spreads statewide.

A smoke advisory for a broad swath of Southern California was extended into Thursday night due to brush fires in Los Angeles and Riverside counties. The Sandy Fire in Simi Valley and the Bain and Verona fires in Riverside County have resulted in diminished air quality this week for several counties.

There are currently seven wildfires burning around Southern California, some of which are threatening homes and prompting evacuations. The largest of the ongoing wildfires is the Santa Rosa Fire on Santa Rosa Island in Channel Islands National Park,

On Tuesday, fire officials said the Sandy Fire had experienced significant growth due to shifting winds, steep terrain and canyon-driven fire behavior.

Wildfires have started from glass bottles, gender reveal explosives, target shooting, vehicle sparks and other unusual ignition sources.

Officials say record-low Sierra snowpack is an early warning sign for California.