Two large Nevada wildfires are racing through rugged mountain regions making it hard for firefighters to tame the blazes.

Officials are trying to add resources to fight the flames. One fire’s smoke can be seen from downtown Las Vegas and the second is southwest of Reno.

The fire northwest of Las Vegas on Mount Charleston is only 15% contained after eight days. The fire is believed to have been sparked by lighting and has grown to almost 31 square miles or roughly the size of Manhattan. The fire came within a mile of about 400 homes. Over 500 residents and a state youth correctional camp have been evacuated. All roads into the region are closed.

“It’s dry,” U.S. Forest Service spokesman Jay Nichols told reporters. “We’re being extremely careful and monitoring the safety of firefighters and the public.”

The second fire grew Monday to 40 square miles in the Pine Nut Mountains near Reno and Carson City. A fire spokeswoman told FOX News that 720 firefighters are on the front line and that they’ve only had one injury while fighting the blaze. The fire was reported to be only 25% contained as of Monday night.

The mountain range stretches to the state capital of Carson City. Back roads from the mountains to the capital have been shut down due to the fire threat.