They're usually good up to the bottom of the tank, anything over that they will start sucking water in the clutch intake and start slipping the belt. Doubt it was taking in water in the engine, water doesn't compress!
Make sure the plug boot is in good shape and sealing. And if you have an older (600) Grizz, which is aircooled, they are more affected by water crossing as it cools down the engine so much it will start running like it's a cold day and stall (need choke).
Your best bet is probably an online order for a snorkel.