If you are at a point when the blower is under water I would be far more Worried about the starter and alternator than the fan motor! However haveing done that sort of washing myself all I have ever done is then run it afterwards to try and get it all moving and flush out anything that has got into it.
Just make sure the drain at the bottom of the fan case is open and use it [ the blower and the land rover over the next few days ] get every thing warm, don't let it stand