The release of The Empire Strikes Back in 1980 brought a number of new ideas and designs to Star Wars, including new creatures, new ships, and, yes, even a new Stormtrooper design. Though we'd seen some slight variations on the standard armor in the first film, The Empire Strikes Back gave us what are technically known as "Cold Weather Assault Stormtroopers" and known to fans as "Snowtroopers." (In-universe, "Snowtrooper" would eventually be the official name of the First Order's cold-weather troopers.)
As their name suggests, the Snowtroopers are Stormtroopers who've been trained and equipped for frigid environments like the ice planet Hoth, where they first appear in the franchise. In addition to knowledge that helps them survive in frozen climates, they're also equipped with more hood-like helmets that help keep out the cold, as well as heated breathing apparatuses, battery packs to help those apparatuses stay operational, snow boots, insulated armor, and more. While the original Stormtrooper design is meant to evoke a skeleton, the Snowtroopers look almost like ghosts, which adds to their menacing appearance in snowy environments.
