ginger zee and talk about what's going on on the west coast. Ginger, you and I have been talking about it. Too much too fast That's going to be the problem. See, they're already seeing rain. Los... See More
ginger zee and talk about what's going on on the west coast. Ginger, you and I have been talking about it. Too much too fast That's going to be the problem. See, they're already seeing rain. Los Angeles close to an inch overnight but it came over four or five hours. That would not be a problem with storm one. Month ray picked up some 4 inches around that region. But it isn't only storm one we're concerned about. It sounds like thing one and thing two. It comes tomorrow. Most of Thursday is dry but Friday morning, 2:00 A.M. Where we start to see the rain and thunderstorms, gusts up to 60 miles per hour, enough energy in the lower atmosphere to twist a little. We co-so waterspouts become coastal tornadoes. Something pretty wild and rain almost all day on Saturday too so here's the deal. You put four to six inches of rain very quickly, I mean an inch an hour at times on the mountains, you're going to pick up close to a half foot in places like Glendora where they had a fire recently, that's going to be an issue and that's where we find David Wright this morning. Reporter: This neighborhood just survived the winter wildfires a couple of weeks ago. Now they're nervous about possible mud slides. As you can see the whole place looks like a for tress here bracing for what may come. It's California's worst drought in 150 years and the rains are coming. About to pose serious problems of their own. One thing after another. The fire was one thing but we've got another one right behind it. Reporter: Some areas that faced wildfires last month are now bracing for mud slides. A lot of folks here that are really scared. Reporter: The scorched Earth is not equipped to handle all that water. Which can turn into flash floods and mud slides. If we have a combination of storm and high tide, we can have significant flooding. Reporter: Overnight, residents all too familiar with the danger rushed to pack sandbags. Get out of here. Reporter: Hoping to prevent entire hillsides from slipping and sliding like muddy Jell-O. I think we're all pretty worried about what's going to happen. Reporter: The worry is that the drought and the wildfires have weakened the ground cover and that could lead to a tidal wave of mud and what they're trying to do here is build a funnel and basically funnel it down the middle of the treat and keep the homes intact. George. So much coming in.
This transcript has been automatically generated and may not be 100% accurate.