First thing that came to mind when I saw the picture was getting into deep water that washed over the bonnet, up on the bulkhead and windscreen and back into the intake - hydrolocking the motor
------ Follow up post added October 4th, 2016 09:11 PM ------
Probably unlikely but I've had water come up that far crossing rivers and driving into a hole.
2011 RR HSE -
1970 LR Series 2A Bugeye BenzOver
2001 GMC 2500 4wd