Originally Posted by skimmer

Safer to walk any unfamiliar water crossings before committing a fully laden bike into the unknown.
Hidden obstructions, soft river beds and water that comes up to bottom of your 'arris will all cause your bike to stop suddenly and usually results in a lung full of water for the bike.
The snorkel only sits approx. 50mm higher than an intake without, so any of the above will cause the bike to take a drink with the engine running.
If it stops abruptly, it's time to remove the spark plug before touching the starter to avoid the risk of a hydraulic con rod breakage, water won't compress.
Extreme precautions to take are an extension from the front of the snorkel with something similar to vacuum hose to a position above the bars, a system often employed when preparing a bike for the Wild and Woolly motocross where they send you through skips that are filled with water.