Shed hunting in the snow can be better at times because the bones stick out like a sore thumb rather than blended in with the ground. It takes quite a bit of snow to cover up a shed completely. Yes some of it may be covered but keep an eye out for tines or burs sticking up. Sometimes you will get a big snowfall early which will freeze in hard and form a crust, then any shed after that time will be held up on that crust rather than sinking down to the bottom. If you get a huge dump of snow while they are shedding hard then yes it will be difficult, but snow at certain amounts and times can be your best shed hunting tool.