PLUMAS COUNTY, California - For three weeks, the Dixie Fire has grown to over 428 square miles (1,108 square kilometers) across California's Plumas and Butte counties.

As the state's largest active wildfire, it's destroyed more than 100 homes and appears on its  way to do even more damage.

The #DixieFire is now the 6th largest fire in CA history at 322,502 acres. As we head into the weekend, triple digit temps are expected in many parts of CA! Avoid the sparks that start wildfires by never using outdoor equipment or driving a vehicle on dead or dry grass. pic.twitter.com/SsXWRlIGth

— CAL FIRE (@CAL_FIRE) August 5, 2021

CNN reports that authorities are working to find four people who were unaccounted for due to the fire in Plumas County. 

Plumas County Sheriff Todd Johns said, "What I am telling folks at this time is if a plume of smoke is anywhere near your direction and you're still miles away from it, you need to prepare [to leave] even if you haven't heard that you are under a warning." 

The fire has nearly leveled California's historic town of Greenville, where the community's commercial center at Main Street and State Route 89 has been left in shambles, with nearly every business collapsed or gutted.

The most recent evacuation orders issued were in Lassen County, and apply to areas north and east of Mountain Meadows Reservoir.

Yet another fire rages 80 miles south of this area and over 800 first responders are working to fight the blaze.

The River Fire in Nevada and Placer counties has demolished at least 76 structures and approximately 20 structures have been damaged, according to Cal Fire's Thursday night update.

Damage assessment has yet to be finalized, as inspectors are still not able to access all affected areas.

Two residents and one firefighter were injured in the fire.

Over the summer, a series of deadly heatwaves coupled with historic drought have made wildfires harder to fight in the U.S.'s western regions, experts say.

Scientists believe climate change has contributed to much warmer and drier conditions in the West for the past 30 years. They anticipate this trend is will continue and result in even more extreme weather and increasingly frequent wildfires.