Both global warming and the popularity of downhill skiing are on the rise, a trend that probably seems a little counterintuitive. Hiding behind the scenes are snowmaking machines, which every year convert millions of litres of water into money-making snow. YouTuber Tom Scott went to Norway to get an understanding of the basic science behind snowmaking, and also the scale needed to blanket an entire mountain in man-made snow. The machines use a fan to accelerate a finely-tuned mix of water and air at high speeds, evaporating some of the water. This cools the remainder, causing a few tiny rain drops to freeze into ice particles and giving nucleation sites for the rest of the water to turn to snow. It's a faintly similar process to what happens in a cloud, just sped up and then ploughed into the shape of a ski slope.
With global temperatures on the rise, the importance of snowmaking for resorts has grown precipitously. The first snowgun came into use in 1952, with widespread adoption following in the '70s and '80s, as bigger resorts wanted more reliable weather.
As it turns out, snowmaking is an environmentally awful process. The water has to come from somewhere, and in many cases, that's local lakes and reservoirs, which sometimes don't go back to their pre-skiing state when the snowmaking is finished. Worse, the electricity needed to power one single snow machine for a season is enough to run three average households for a year, and big resorts need hundreds. Ironic, for sure, but you probably won't be laughing when your next ski trip turns into a mountain-biking holiday.