A Blizzard is a periodical event in-game. During a Blizzard, Snow and Ice regeneration rates accelerate greatly, quickly refreshing areas that might have been shoveled, plowed, mined, or otherwise collected to virtually nothing.
Blizzards begin with a notification across the middle of the screen (see right) which reveals dense airborne snow particles once it retreats. This dense particle field reduces visibility greatly, making accurate navigation, whether on foot or by vehicle, a difficult task. Zooming in to first-person mode helps abate this effect a little.
Inspired by this phenomena is a premium Snow Tool, the Blizzard Bomb, which offers a similar regenerative effective, but on a much smaller scale.