ST. LOUIS – No, it wasn’t a runaway dumpster you heard Sunday morning. It was a thunderstorm. Scientifically speaking, it’s not much different from our usual thunderstorms.

Thunderstorms and thunderstorms are quite rare. For lightning to strike and thunder to boom, the air must be unstable. Under typical conditions, thunderstorms occur with warm air well above the ground. Apparently the air wasn’t warm on Sunday.

What happens far above our heads is buoyancy. The warm front to our south is adding additional energy to our snow and sleet clouds. The result of this burst of energy is thunder and lightning.

Thunderstorms sound a little different than normal thunderstorms, almost muffled. Instead of a quick clap of thunder, it’s more of a low growl.

The green spots in these satellite images are lightning bolts as seen from GOES-East in space! That means…

There are thunderstorms/thunderstorms! This just highlights that snow/sleet rates are quite high – avoid travel if possible! pic.twitter.com/8I9sSVfXVo

– NWS St. Louis (@NWSStLouis) January 5, 2025

It’s certainly strange to hear thunder while something as still as snow is present, but that will be the case all day Sunday. Combined with sleet, you will hear rumbling thunder mixed with the sound of tiny knocks.