The northern Oregon coast has had a remarkably snowy week — white snowfall blanketing cities, bringing sea lions to hotel patios in search of warmth and surfers to Seaside to glide amid the winter weather.

And in Astoria, frosty conditions have brought about another unusual weather phenomenon: thundersnow.

Around 1:15 p.m. Wednesday, radars picked up indications of thundersnow about 5 miles southeast of Astoria, according to the National Weather Service in Portland.

“This is not often seen in this area,” the weather service said, “but how cool is that?”

What is thundersnow?

Despite its intimidating name, the rare winter phenomenon is more or less what it sounds like: snow, paired with thunder and lightning. It’s a thunderstorm — but with snow instead of rain.

Thundersnow occurs in areas of instability, when warm, moist air rises and settles below a mass of cold air, forming puffy cumulus clouds, according to the National Oceanic and Atmospheric Administration. These are the standard ingredients — moisture, instability and rising air — for a thunderstorm, but they rarely come together during winter storms because the air tends to stay evenly cold.

It’s a weather event so rare that Weather Channel meteorologist Jim Cantore erupted in shouts of excitement when he witnessed thundersnow during a 2011 Chicago blizzard. Earlier this year, bursts of thundersnow sparked along the East Coast and Midwest.

What fell in Astoria was a mix of both snow and ice pellets, the National Weather Service in Portland clarified in a reply to the original post.