We begin here with a tale of two nations tonight. Fire and ice, as I mentioned. And look. In the west, hall continuers in the air this evening. Firefighters on the ground there, doing battle with the powerful flames. And then this image tonight from the heartland, wisconsin, believe it or not. A blanket of snow in may. And we have learned tonight that these weather extremes all being fueled by the same system. We get to it all now, beginning with the fires, and this from our power house station, kabc in los angeles. Their cams are capturing the fire. Abc's david wright starts us off with an abc news exclusive. The firefighters on the front lines, allowing us to come along with them. Reporter: One of the most see nick highways in america. Tonight, the front line of the biggest wildfire in the west. Today, abc news cameras got right into the heat of the day's biggest hot spots. A blaze pushed in one direction by hot wind from the desert. I'm not worried what's in front of us. Reporter: And now pushed the other way by a cool ocean breeze. It's swirling around. It comes from every direction. The wind is just shifting continuously. Reporter: Whipping up walls of flame, 150 feet tall. Helicopters attack from the air, but they're only aided them to cover 10,000 acres. On the ground, 1,000 firefighters form the infantry. They have to be plumbers, as well as foot soldiers. Bringing the water right into the flames. Stopping the fire in its tracks. Today, they raced to save a coastal naval base. Kabc reporter john gregory was there. Structure protection crews from all over southern california here. They are focusing on this training facility. They are trying to protect it from the flames. Reporter: One thing about fire, it tends to burn uphill. Steep terrain like this acts like a chimney. That house is in real jeopardy. Ted fisher sprayed down his house in an effort to save it from the flames. Invested a lot in this house, a lot of time. And thmemorimemories. I don't want to us loo it. Reporter:4,000 homes are currently under threat. 15 of them have been damaged. But astonishingly, none of them destroyed. And firefighters here are doing everything they can to keep it that way, david.