Usually when you drive through Mesquite, NV on I-15, you can barely tell that there is any sort of river down there. This is the view that Mike and I saw on our drive back to Cedar City from Damian and Tandy's in December. It was quite the flood.
Above is looking east toward Mesquite and Bunkerville (Just south of Mesquite proper). The mountains are shrouded in clouds and the rain just kept coming. It was earlier this day that homes just north of here in Beaver Dam, AZ, were washed away. That might have explained why I saw a large track hoe working at the river's edge just north of Mesquite. It might have been pulling out pieces of homes that were floating by.
Below is in St. George as we passed over the bridge. The bridge just barely cleared the water. Usually it's just a very small stream. (They call it a river here, but really? Compared to the Red River and the Mississippi? Just a stream)
The photo below was taken in the Virgin River Gorge.
Another view in the gorge is above. Below is another shot going through Mesquite. They aren't in order (of course!), but at least you can get an idea of the massive amount of water that was moving through that place. It was amazing to see that much water in our desert. It didn't stop raining until we got to Cedar City, and it had been raining there for three days, too!