We had some flash floods in AZ this weekend. Kind of awesome.
These are from Wickenburg. Note that the place and the 'river' channel were bone dry before the storm passed through.
https://www.youtube.com/watch?v=Sgi3w24NPbI
https://www.youtube.com/watch?v=EPsB1zLFj_o
https://www.youtube.com/watch?v=Kzu7o8VH5GY