The first big blast of winter weather in the United States this week brought snow, frigid temperatures and, in some places, something even more magical: frost flowers.
Made of thin ribbons of ice that stretch in complex patterns when freezing water penetrates the crevices of certain types of plant stems, ice flowers can disintegrate with a single touch and are only visible for hours at a time.
They are found most often in the eastern half of the United States, especially in the upper half where hard freezes are more common, and resemble clouds of cotton candy or spun glass.
For some, it has become a well-known phenomenon, signaling the approach of winter and getting people out of bed to take a look before the daytime sun melts them.
On Monday and Tuesday, people in Indiana, Missouri, Tennessee and elsewhere posted photos on social media showing fields and backyards filled with iconic pieces of natural art in the early hours after the deep freeze.
“You have to be at the right time, in the right place,” said Alan Templeton, a professor emeritus at Washington University in St. Louis, Missouri, who does a lot of research in conservation genetics. “You see them and you know they’ll be gone in an hour or two. So, this beauty is ephemeral, but very changeable, and that combination is what makes me so fascinated by them.”
While complex ice patterns have been found near the base of a few common plants, including white and yellow lacewings, Templeton explained that conditions had to be just right for them to appear. Once they do, they won’t come back for another year.
The ground must be warm and moist enough for water to move from the plant’s roots to the stem, while the air must be cold enough to freeze the liquid so that it penetrates the stem and creates a flower-like appearance.
It’s only found in a few different plant species, he added, because the phenomenon can only happen if the stem was able to hold water in the fall or early winter and was weak enough to withstand ice pressure. Plants also need a particularly active root system later in the year.
Templeton said he first encountered frost flowers in decades while exploring an area in the Missouri Ozarks for field work.
“They are really beautiful,” he said. “And also each one is unique. No two frost flowers are the same.”
On Monday, after noticing that weather conditions would be ripe for this phenomenon, he set off to a protected area in St. Louis County where he has found hundreds in past years. This time, there were only about two dozen, which he said was likely due to them showing up earlier than usual and temperatures not dropping enough.
Crystal Liggins has lived in Tennessee most of her life, but she said she discovered frost flowers only three years ago when her family moved to a rural area of the state.
After seeing them along a small patch of unprotected land while driving to work in Mackenzie, about 47 miles (75 kilometers) northeast of Jackson, she said she initially thought they were spider webs or silkworms. When she got out of her car and picked them up, she said they were crushed in her hands.
“People live here their whole lives and never know they exist because they never see them or they are never in the right place at the right time,” she said.