Snow Trooper

The Snow troops or cold attack troops, named because of their area of operation,
were specialized storm troops of the Galactic Empire. Trained and equipped, 
to operate at temperatures below the freezing point of water. They are Imperial Elite Stormtroopers.
 

Since the Empire found only particularly talented and special recruits useful for this unit,
certain soldiers received psychological and military training at the beginning of their training in order to strengthen the snow troop divisions.
The fellowship at the snow troops was usually so strong that only a few wanted to ever change their units.

Due to their areas of application, which could not always be reached on foot,
they were usually transported in groups of around 40 people to the rear of the AT-ATs.

Source: https://jedipedia.fandom.com