Will California wildfires merge into massive inferno?

Giant wildfires grow in California during hea... 02:23

At least 16 wildfires are raging in the West and an extreme heat wave is making matters worse, bringing sweltering triple-digit temperatures in some areas.

Two wildfires north of Los Angeles have scorched more than 4,500 acres. The flames from the Fish fire and Reservoir fire ate away at the tinder dry vegetation Monday. Firefighters mounted a strong offense in punishing 100-degree heat, in order to keep the fires -- that are separated only by a canyon -- from merging into one massive inferno.

Wildfires, heat scorch the Southwest 02:08

Smoke choked the air and became an eerie backdrop to the downtown Los Angeles skyline. Drivers could see the towering plume from the freeway.

More than 600 homes are under mandatory evacuation. Some people had little more than 10 minutes notice before they had to get out.

"It's devastating. It's unbelievable how fast it happens, that it was actually burning against the wind downhill," said Frank Tamuro, a resident who was forced to evacuate."

Debbie Crawford watched anxiously as the fire flirted with her property line.

""If this burns, we know the next thing will be mudslides. We live here for a reason. We love these mountains and these hills," Crawford said. "When you live in some place like this, you've got to know there's always that danger, so there's a trade-off."

As night fell, the flames crept closer. The air assault pressed on and the camp crews fought the fire from the ground.

"With this heat and with the fuels being so dry we could have another spark-up a couple of miles away," said Gustavo Medina, an inspector with Log Angeles County Fire.