Much of the SouthCoast heard or saw thunder and lightning in the middle of Thursday's snowstorm, with the most prominent thunder reported around noon in New Bedford, Dartmouth and Fairhaven. It's a rare phenomenon, reported only 6.3 times per year in the United States on average. But what is Thundersnow and what causes it?

Most snowstorms develop from flat, layered snow clouds that form below 20,000 feet, according to The Weather Channel. When those clouds form bumps, or "turrets" they rise upward above the rest of the flat snow cloud by about 5,000 feet. The turrets create a strong upward motion of warmer air that combines with colder air above. When temperatures are in the appropriate range (14 to minus-4 degrees Fahrenheit) both snowflakes and small hailstones that resemble sleet form.

As these particles bounce off each other, electrical charges can develop. It's not all that different from shuffling across a carpet in your socks to create friction, then giving someone a shock. This electrical charge is then released in the form of lightning, sometimes cloud-to-ground and sometimes horizontally within the cloud. It can be seen and heard in a smaller geographic area than a thunderstorm because the snow acts as an acoustic muffler.

  [View the story "Winter storm hits New Bedford on Feb. 9" on Storify]