The first major blast of wintry weather in the U.S. this week brought snow, frigid temperatures and in some places something a little more magical: frost flowers.

Made of thin ribbons of ice that extend out in intricate patterns when frozen water breaks through certain plant stems, the icy blooms can disintegrate with a single touch and only appear for hours at a time.

They are found most often in the Eastern half of the U.S., especially in the northern areas where hard freezes are more common. Resembling clouds of cotton candy or spun glass, frost flowers have become a well-known indicator of winter, prompting many to rush outside to witness their beauty before the sun melts them away.

On Monday and Tuesday, people from Indiana, Missouri, Tennessee, and other states shared images of their backyards and fields filled with these natural artworks shortly after a severe freeze.

“You have to be at the right time, at the right place,” said Alan Templeton, professor emeritus at Washington University in St. Louis. “It’s a beautiful, but ephemeral phenomenon.”

While frost flowers can form near the bases of certain plants, conditions must be just right, including wet, warm soil and freezing air, to create these unique structures. Templeton noted that they are delicate, with no two frost flowers identical.

Finding them is a bit of luck; first-time observers like Crystal Legens from Tennessee initially mistook them for spider webs. Once they’d learned about frost flowers, many residents found themselves enchanted by their fleeting beauty.

Templeton mentioned that he first came across frost flowers several decades ago and continues to be fascinated by their intricate design. They symbolize the unique magic of winter that many locals and adventurers cherish.