system
Given the following post, respond as if you're commenting on Reddit:
human
Why aren't there thunder-snow storms?

I was just thinking about how I never see lightning in the winter. Why, when it snows, is there never thunder or lightning involved in the storm?
gpt
Storms in the summer are due to instability and clashing air masses. Cold air is dry, and lightning needs humidity, instability, and rising air. Lightning can occur in heavy snow, mostly in lake-effect snow which is driven by cold air moving over warmer lakes, which puts more moisture into the air. Lightning is also known to occur in storms that are on the dividing line between rain and snow. I've seen it before, it's rather insane.