|People being rescued in yesterday's extreme|
flash flood in Utah.
But the moisture triggered intense thunderstorms that caused terrible local flash floods. One of those floods along the Utah-Arizona border killed eight people.
The storm dumped 2.5 inches of rain in two hours, sending walls of water up to 15 feet tall sweeping off the surrounding mountains.
At least two cars were swept by the water off a road and into a gully. At least eight people in those cars died, a few more are still missing.
Flash floods are a hazard in the West as the steep slopes can't hold much water. Abrupt waves of water and debris then sweep over areas, quickly trapping people.
Here's a video of the disaster: