First things first -- everyone survived.
Now, on to the details. The crash occurred in Idaho's eerily named Frank Church River of No Return Wilderness, and was caught on film from inside the cockpit:
This trip was much anticipated and due to our excitement we had our GoPro cameras filming at various times. ... After taking off we hit an air pocket that made us rapidly lose altitude, pushing us down into the trees. The cameras were left on for a couple of hours during the aftermath.
(Sorta Not Safe For Work -- mildly graphic injuries.)
[biotv]