A blizzard requires three things to form: temperatures below freezing at ground level and in the clouds to allow snow to form, enough moisture to allow clouds and eventually snow to form, and a mass of warm air rising over a mass of cold air that creates strong winds. Bizzards are typically formed when a high-pressure system meets a low-pressure system.
Not every severe snowstorm is considered a blizzard, and in fact, a blizzard doesn't even need to involve much snow. The National Weather Service has a set of three criteria that must be met for a storm to be considered a blizzard. First, there needs to be blowing or falling snow that results in a reduction of visibility to less than one-quarter of a mile. Second, the storm needs to produce sustained winds or frequent wind gusts in excess of 35 mph, and finally, the previous two conditions need to continue for at least three hours.
Many blizzards do not involve heavy or wet snow but instead very light snow, which has quite minimal water content and easily is blown around by the wind. Even though the East Coast of the United States typically gets more snow, blizzards are much more common in the northern Midwest due to the high wind factor in that area.