A blizzard isn’t just “a lot of snow” – it’s a specific kind of intense snowstorm with strong winds and very low visibility for several hours in a row.

Quick Scoop

In places like the U.S., weather agencies define a blizzard as a snowstorm that meets all of these conditions:

  1. Strong winds
    • Sustained winds or frequent gusts of at least about 35 mph (around 56 km/h).
  1. Very low visibility
    • Falling and/or blowing snow reduces visibility to a quarter mile (about 400 meters) or less.
  1. Lasts for hours, not minutes
    • Those conditions persist for at least 3 hours in the U.S. (often 4–6 hours in some other countries’ definitions).

So, what makes a blizzard a blizzard is not how deep the snow is, but how powerful the wind is and how badly it cuts visibility for an extended time. You can have a huge snowfall that’s not a blizzard, and you can have an official blizzard with only modest new snow if winds are whipping existing snow into whiteout conditions.

Blizzard vs. “just” a snowstorm

  • Snowstorm: Snow is falling, maybe lightly to moderately, with weaker winds and you can still see a decent distance.
  • Blizzard: Snow plus powerful winds that blow snow around so much you can barely see, and it stays that way for hours.

One-sentence version

If the snow is heavy, the wind is howling around 35 mph or more, you can’t see much beyond a house or two away, and it keeps going for several hours, that’s what officially makes a blizzard a blizzard.

Information gathered from public forums or data available on the internet and portrayed here.