Many Baltimoreans learned a new word last night — “thundersnow.”
It sounds like a Pokemon’s superpower (Your guy has Shock-wave? Mine has Thundersnow!) It’s also the name of a heavy metal band in Rochester. But meteorologically speaking, it is actually a rare and powerful weather phenomenon.
We experienced it as a muffled 3 a.m. BOOM, a flash of light outside and an apparent surge of energy through our house’s electrical system that set off a security alarm and made the lights flicker. Earlier in the evening, what we later deduced to be another thunder snow phenomenon knocked out the television and burned out a surge protector.
Christine Dell’Amore, writing in National Geographic News describes thundersnow this way:
The sun heats the ground and pushes masses of warm, moist air upward, creating unstable air columns.
As it rises, the moisture condenses to form clouds, which are jostled by internal turbulence.
The “tricky part” for making thundersnow, (Patrick ) Market said, is creating that atmospheric instability in the wintertime.
For thundersnow to occur, the air layer closer to the ground has to be warmer than the layers above, but still cold enough to create snow—a very precise circumstance.
- by Fern Shen


