DENVER (KDVR) — A storm on Sunday dropped rain, hail and snow across Colorado, which caused some traffic issues on Monday morning. But the storm brought more than just a couple of inches of snow – it also brought a rare weather phenomenon.

A viewer of Nexstar’s KDVR captured the unique event on video.

At first, the video shows a mix of rain and snow falling outside a home on Lookout Mountain. Then, about 25 seconds into the video, thunder erupts, lasting almost 10 seconds.

This phenomenon is known as thundersnow, which is a thunderstorm in the winter.

How thundersnow works

While thunder is less common in the winter, it can happen. Thundersnow is the same as a thunderstorm, just with snow instead of rain, according to Pinpoint Weather Meteorologist Greg Perez.

It doesn’t normally happen in the winter because there isn’t as much energy in these types of systems, said Perez. Usually, in snowstorms, there is a lack of heat and low cloud levels.

However, during the storm on Sunday, the temperatures were warm enough for a thunderstorm but cold enough for snow.

Lookout Mountain had just enough moisture for the rare occurrence, said Perez.

Thundersnow is also rare because oftentimes, it goes unheard. When thundersnow happens, the snow often muffles the sound. This makes the video above especially unique, as the thunder can be heard for almost 10 seconds.

While there aren’t specific records as to how often thundersnow occurs, Perez said it’s extremely rare, especially in Colorado.