According to wikipedia, a blizzard ain't a blizzard until:
1. There is snow or ice precipitation
2. Visibility must be reduced to 1/4 mile (400 km)
3. Wind speed must be at least 35 mph (56 kph)
Here's footage of a blizzard happening outside my door right now. [blizzard movie]
UIUC never closes because of snow, but today, classes are canceled and movement is down to almost nil. The snow ploughs are working over time and the snow just keeps coming and coming...estimated about a foot or more of snow by the end of today.