The savage strength of this system takes over with ease in mere moments.

A video of a flash flood at Arizona's Tonto National Forest that occurred last Saturday has gone viral. The flood takes a minute or two to materialize, but once it starts it moves with a frightening swiftness. You can fast forward to the two-minute mark to see the action get going in earnest, but we recommend watching it from the get-go to see what the land looked like pre-flood and how quickly the topography changes.

And while this clip makes it seem harmless, the sad reality is the floods that ravaged the area had fatal consequences, as nine people died -- all from the same family -- and one went missing as a result.