As of Monday evening, the blaze grew to 23,600 acres with 5% containment.

Firefighters battling the Line Fire in San Bernardino County remain concerned the 23,000-acre blaze could grow significantly within the next 48 hours as they face unfavorable conditions that are feeding the fire.

Amid triple-digit temperatures in this sweltering heat wave, more than 1,700 firefighters are working to contain the massive blaze ripping through the San Bernardino National Forest. The fire began Thursday night and as of Monday evening, swelled to 23,714 acres with 5% containment.

"Really tough fire, still," Cal Fire Battalion Chief Brent Pascua said. "Same conditions as the last few days - hot, dry and we have thunderstorms predicted again for today."

The hot weather, coupled with steep terrain in remote areas, has proved to be a challenge for crews working tirelessly to upend the blaze, which is threatening about 36,000 structures. Three firefighters were injured in the blaze.

Due to the fire, Bear Valley Unified School District canceled classes for Monday and Tuesday.

Gov. Gavin Newsom also issued a state of emergency because of the fire. The National Guard is slated to be deployed to evacuated areas to help law enforcement keep order.

The following evacuation orders and warnings have been issued: