What a Blizzard Is and Is Not as Explained By ABC News Meteorologist

— -- As an estimated 60 million people brace for a potentially historic snowstorm across the East Coast, the National Weather Service began issuing blizzard warnings for part of the area beginning Friday afternoon.

So does a blizzard mean that a lot of snow is expected to fall?

ABC News Meteorologist Melissa Griffin explains:

1. WHAT IS A BLIZZARD?

“A blizzard actually doesn’t have to do with snow totals," Griffin said. "For blizzard conditions, all you need is three hours or longer of sustained winds or frequent gusts up to 35 mph and reduced visibility to less than a quarter of a mile.”

2. WHAT ARE SOME MISCONCEPTIONS?

“The biggest misconception is snow accumulation. You can actually have a blizzard without snow falling. It’s called a ground blizzard. It goes back to what I was saying before, as long as you have those conditions, the wind and low visibility, you can have a blizzard."

3. SO THERE CAN BE BLIZZARDS IN THE DESERT?

"No, there has to be snow on the ground already for there to be a blizzard," Griffin said. "Ground blizzards use the snow on the ground to make those conditions, we call it blowing snow. But, the snow doesn’t actually have to be falling from the sky at that moment for it to be a blizzard."

3. WHAT’S THE DIFFERENCE BETWEEN A BLIZZARD WATCH AND A BLIZZARD WARNING?

“When you have a blizzard watch, that area could see blizzard conditions within the coming days. It’s not a guarantee yet," Griffin said. "When you have a blizzard warning, that means blizzard conditions are imminent: confidence is basically high that blizzard conditions will start and meteorologists are not going back and forth. When we have a watch, we aren’t sure yet.”

“We get the watches and warnings straight from the National Weather Service," Griffin said. "They make those decisions. They update the watches and warnings when conditions look to be imminent and when we get close to the event.”

5. WHAT CAN PEOPLE DO TO STAY SAFE DURING A BLIZZARD?

“The best thing to do is to NOT DRIVE. Don’t travel, stay home, stock up on supplies for at least two days. But really, the worst thing you can do is get in your car and drive during a blizzard.”