We seldom get water moving fast enough in my immediate area to wash a car off the road, unless it is quite deep and due to a recent failure of a levee, although it does happen. Most of it just sort of "oozes in."

The most common hazard is that the road goes in on one side and comes out on the other, but in the middle the road is GONE. In open country, the INVISIBLE missing part of the road can sometimes be to a depth of several feet.

In Arizona, on a cloudless day, we came upon a "gully" that was about 6" deep when we saw that there was water there, but was about a foot deep by the time we got to it.

I stopped and waited.

Three cars that went around me and tried to drive across ended up downstream in the middle of the desert - one about an eighth of a mile away.

One other car that "stuck" and stayed on the road demonstrated the speed of the flow, as you could see pavement beside the tires on the downstream side (maybe 3" deep), but water was coming in the windows on the upstream side.

I waited about 45 minutes and drove across on DRY pavement. (Wet pavement does dry quickly in the Yuma vicinity.)

The rain that caused it was a small shower about 15 - 20 miles away, not visible from where I met the runoff. A later check with the weather guys indicated that the water didn't arrive at the road until about 45+ minutes after the rain stopped. One of our chopper guys claimed to have followed the "front" about half way to the road, and had radioed a warning back to the base, so there were pretty good descriptive records of what had happened.

Amazingly, all the cars washed downstream stayed right side up, and were operable once we dried a few things out. They were incredibly lucky.

John