In La Nina winters, nature doesn't always provide natural snow to help ski areas open. Across the U.S. and around the world, resorts often use machines to build base depths when nature can't provide it itself.

But this snow behaves differently than natural snow. Expert skiers and boarders can tell the difference. Even if you can't, the science is interesting and the implications are important if you do ride. The snow they make has some benefits and drawbacks compared to the stuff that falls from the sky.

There are two types of snow guns — machines that make snow. They operate differently but both types take water, turn it into tiny droplets, add some particles to freeze onto, and add a powerful stream of fast-moving air to propel them into the air. They differ in whether that air is gene

See Full Page