I don't think it's an issue of 'snow,' but an issue of water temperature (dropping air pressure
will effect the fish/fishing). Fish, being 'cold blooded, take their body heat/metabolism settings from the surrounding water. (From what I know anyway) The best range for 'trout' is mid-40's to about 52 degrees (sorry that's in F's, not C) and above/below that the fish tend to go 'dour.'
All that said, call the venue and ask them what the water temps are running, perhaps a clue if it's worth the Petrol.
fae
Edit: "The simple answer is no, i have caught rainbow while half the lake has been frozen, and also rainbow trout are native only to the rivers and lakes of North America, west of the Rocky Mountains, which gets alot of snow lol" Sorry G19, you were posting as I was typing, agree totally.
Fred