Evacuation orders have been issued in several regions in the West due to spreading wildfires.

       Thousands of residents in Northern California and Montana were ordered to flee their homes as both new and existing wildfires neared neighborhoods.

       Currently, about 90 large wildfires are burning in 12 states in the West -- much of which is suffering from severe drought conditions.

       Nic Coury/The New York Times via Redux Pictures

       The Dixie Fire burns near Taylorsville, Calif., July 29, 2021.

       The Dixie Fire, which has been burning near the Feather River Canyon in Northern California for weeks, prompted new evacuation orders in Greenville.

       MORE: More wildfires possible in the West as fire conditions worsen

       The Dixie Fire -- the largest in the state -- has been through more than 253,000 acres and is just 35% contained. The extreme fire behavior is being exacerbated by hot and dry conditions with gusty winds are persisting in the area, making it difficult for firefighters to battle the blaze.

       The McFarland Fire in Wildwood, California, prompted evacuations in the area after it grew to more than 15,000 acres and remains just 5% contained. Critical fire weather is in effect in the region through Wednesday.

       USFS/EYEPRESS via Newscom

       Firefighters battle the Dixie Fire, which has burned nearly a quarter-million acres, Aug 3, 2021.

       Evacuation warnings are in effect for the Monument Fire in Big Bar, California, after scorching through more than 6,000 acres. It is 0% contained.

       The Boulder 2700 Fire near Polson, Montana, burned through nearly 1,500 acres by Tuesday afternoon and prompted evacuations over the weekend. Multiple structures have been destroyed by the fire, but cool, wet and humid weather will help to contain it.

       MORE: Pacific Northwest braces for another heat wave as dozens of wildfires continue to burn

       The spread of the wildfires had slowed last week but picked back up as the moisture from the monsoons in the Southwest disappeared, with lightning strikes sparking more.

       At least 35 new wildfires ignited over the weekend due to lightning strikes. Dozens of wildfires have sparked in Oregon alone over the last 48 hours, while 13 new fires have started in the last 24 hours in Montana.

       USFS/EYEPRESS via Newscom

       Firefighters battle the Dixie Fire, which has burned nearly a quarter-million acres, Aug 3, 2021.

       Six states in the West, from Arizona to Washington, are currently under fire and heat alerts, while red flag warnings have been issued in Oregon and Northern California.

       Excessive heat warnings are also in effect this week for the Southwest, including Las Vegas, Phoenix and Tucson, Arizona.

       ABC News' Melissa Griffin and Max Golembo contributed to this report.