There are not companies that make snow specifically for Jeep Wranglers. For a June 2014 commercial shoot in Vancouver, British Columbia, snow was brought in from mountainous areas to help transform a downtown street into a forested, wintry stream.
The process for making artificial snow is fairly consistent no matter which company is performing the task. Snow created for specific events such as movies or the Olympics has dramatically different physical properties than natural snow, rendering it incompatible for using as a baseline for testing vehicles. For commercials, Jeep uses either real snow or generic artificial snow created to give overall effect.