Quit worrying about it. Your engine is not really under any sort of a load. You engine even though it's reving, isn't under the load that it would be at say going WOT up a hill. Heat output of the engine is more a function of load than RPM. You can still rev it pretty high and have the throttle just barely cracked open. As far as cooling, it would be almost impossible to saturate the radiator with heat if everything is working right. Your fine.

As far as your driving technqiue, why are you reving that high in snow? Doesn't doo you any good.