You've probably heard of lake-effect snow, but can you define it? We looked to the National Weather Service for answers.

Lake-effect snow forms when a cold air mass passes over a relatively warm lake. Lake-enhanced snow occurs when a weather system interacts with the lake's moisture.

What is lake effect snow? Lake effect snow is a weather phenomenon that occurs when cold, dry air moves over a large, warmer body of water, such as the Great Lakes.

Lake-effect snow can fall at unthinkable rates, in part because it has a low water content, making it light and fluffy.

The heavy lake effect snow prompted the Buffalo Bills to ask fans for help clearing snow out of Highmark Stadium ahead of the team's game against the San Francisco 49ers on Sunday night.

We thought the lake-effect snow season was over. Our hopes, apparently, rested on thin ice. An unexpected round of lake-effect snow pelted metro Buffalo most of Wednesday. It snarled traffic ...

The Great Lakes contribute to Michigan snowfall each season through the "lake effect." Here's how the process makes snow pile up.

A brutally cold air mass from Siberia meets the record-warm Great Lakes. That’s a recipe for meteorological fireworks. A lake-effect snow event, which started in the upper Great Lakes early ...

Lake-effect snow happens when cold air moves across relatively warm lake waters. Eventually, the warm, moist air rises and forms clouds that move over colder air on land.

Lake-effect snow is something talked about in the Pittsburgh region every winter season, but what exactly is it and how does it occur?

Lake effect snow is expected to accumulate up to 3 feet in some areas of New York today, with travelers being warned not to drive. More ISTOCK / GETTY IMAGES PLUS / NWS What is lake effect snow?