Winter is well underway in the Great Lakes region following a multiday lake effect snow event that dumped several feet of snow in New York, northwestern Pennsylvania and northeastern Ohio.
But, while much has been made of the lake effect snow—which is produced as cold air moves across expenses of warmer lake water—in some areas of New York, residents and storm chasers documented another phenomenon amid the storm: thundersnow.
“Absolutely wild scenes across Copenhagen, NY, and multiple cases of thundersnow,” storm chaser Aaron Rigby said in a post on X (formerly Twitter) on Sunday.
Jeff Swensen / Stringer/Getty
What Is Thundersnow?
Simply put, thundersnow is snowfall accompanied by thunder and lightning. It occurs when conditions are cold enough that a thunderstorm produces heavy snow instead of rain.
The National Weather Service (NWS) describes it as a “rare weather phenomenon” on its website.
The ingredients for thundersnow are the same as a typical thunderstorm: moisture, instability and some lifting mechanism.
Air is unstable if it continues to rise after receiving a nudge from cold or warm fronts. This instability is vital for thunderstorms but rarely occurs when a storm is wintry because they are, by their very nature, cold at both high and low altitudes.
But, on rare occasions like this weekend, shallow layers of warmer air begin to rise, increasing snowfall as they go and generating enough electric charge for lightning—and, by extension, thunder—to occur.
Why Are Thundersnow Storms So Bright?
As many in the region will have noticed, the storms generating the thundersnow were packed full of snow—Copenhagen saw 58.8 inches of snowfall in 24 hours, according to AccuWeather.
This excess of snow falling through the air mixed with lightning amplifies the latter compared with typical thunderstorms, making it appear brighter.
However, while the snow makes lightning brighter, it also makes the thunder quieter.
“While the thunder from a typical thunderstorm might be heard many miles away, the thunder during a thundersnow event will only be heard if you are within 2 to 3 miles of the lightning,” the U.K.’s Met Office said on its website.
Is More Snow on Its Way?
The Northeast isn’t out of the woods yet, as yet more snow brought on by a blast of cold Arctic air is expected in the coming days.
Northern Minnesota, northern Michigan and northern parts of New York and New England can expect steady snowfall over the middle of the week, according to AccuWeather forecasts.
Meanwhile, southwest-facing shores of the Great Lakes are likely to experience intense lake-effect snow, leading to heavy flurries in localized areas.
Expect road closures and near-zero visibility in regions hit by the heaviest snow, although total accumulation is expected to be less than last week.
Do you have a tip on a science story that Newsweek should be covering? Do you have a question about thundersnow? Let us know via science@newsweek.com.
