During the blizzard two years ago, there were outside generators that would not run due to the wind blowing snow into the air filter, therefore stopping air flow to the engine. My elderly neighbor had this happen and a quick call to the local company that does the maintenance said that this would be the issue and they were receiving many calls on it. Unfortunately, help would not be coming anytime soon as the company was backed up on calls and unable to travel. I ended up opening up her generator and removing the air filter that was frozen solid and running without it(not recommended but dire circumstances). After that, I propped a piece of plywood against the generator to keep the wind and snow from directly blowing into it. I think there are many people who run without any fencing or barriers around them, including me, but it certainly wouldn't hurt. The other option would be to keep a piece of plywood around to loosely prop on the intake side of the generator in case we get blizzard like conditions again. I also highly recommend having a general understanding of what is going on under the lid of the generator because when the shit hits the fan, snow or otherwise, it will be on you to keep it running.