Weather systems in middle latitudes generally travel from west to east. Consequently, northwestern Europe receives air that has crossed the Atlantic, gathering moisture as it does so. The ocean is warmer than the land in winter and cooler than the land in summer, so Atlantic weather systems produce wet climates with cool summers and mild winters.
North America has a continental climate. This means the climate is generally dry, with cold winters and hot summers, but with the wide variation that is to be expected over a continent extending from the Arctic Circle to the tropics.
Snow falls in soft crystals of infinite variety, but as the pioneering avalanche researcher Monty Atwater writes, "snow seems averse to being studied. When it is poked or disturbed or manhandled in any way, it changes, quicker than a chameleon, from one kind of snow to another, leaving the observer baffled."
Snow-making and grooming in the Ski Welt is as good as it gets with 434 snow cannons and 624 snow lances up to six meters high covering 210km of 270km pistes and a fleet of 60 Pisten Bully snowcats for grooming.