Cheryl Kimball's Nature Talks: Enjoying a phenomenon from warmer (but still cold) climatesBy CHERYL KIMBALL December 09. 2016 7:34PM
IN THE LATE FALL when the ground is not yet frozen but the temperatures get below freezing overnight, a walk in the woods the next day might reveal some little stalagmites of icicles popping up from moist soil along the path. I always referred to this as “hoar frost.” But a search online explains hoar frost as that light coating of frost on trees and fences on a cold, moist morning. (And the KTTC weather blog out of Wisconsin/Minnesota/Iowa explains “hoar” to in fact mean “gray.”) So apparently, I have never quite known what I was seeing.
What I do know is that those little ice castles poking up from the ground are different from what my cousin in Tennessee takes gorgeous pictures of — ice flowers. These little cold-temperature gems apparently occur at ground level on the deadened stems of the White Crownbeard plant in her field in Tennessee.
In a magazine article Mary Ann wrote about these flowers, she quotes from an online article by Dr. James R. Carter called “Growing Ice — the Many Dimensions.” According to Carter, these ice flowers (also known as “rabbit ice” — among other things, but that’s my favorite) have been noted on as many as 40 different plant species. But the University of Arkansas Cooperative Extension site (uaex.edu) says that “White Crownbeard is one of the most common wildflowers to produce (what they call) frost flowers.”
We in New Hampshire aren’t likely to experience this phenomenon as it happens mostly in areas that don’t have prolonged sub-freezing temps (nor, not surprisingly, where temps never drop below freezing). The culprit in ice flowers is water in the stem of the plant. Mary Ann’s article says:
“ … water in the stem of the plant becomes supercooled: it is below freezing but has not yet turned to ice. In an act of self-preservation, the plant apparently brings warmer water up from the roots, displacing the colder water which has only one way to go — out the pores of the plant stem. When this water encounters the freezing air, it turns to ice.”
The “flower,” however, is yet to come. The ice crystal formed as mentioned above still has water behind it “so that ice crystal is pushed out and another is formed behind it. This continues, creating a ribbon of ice … ”
We see running horses in clouds and people’s faces in the flames of fire and old man profiles in rock formations, something known as “pareidolia.” Ice flowers are subject to this same fantasy; one can see images such as angels in these crystal shapes, although their creation is purely random.
I find this all fascinating — that there are things happening in nature everywhere. No one can be everywhere (or even go everywhere!) so people like my cousin Mary Ann willing to photograph and write about them (and post them on Facebook) allows all of us to get to enjoy the natural world that we may never personally see.
And her article (“Ice Flowers in Henry County,” Paris! Magazine Holiday issue 2013) also seems to explain the ice phenomenon I mentioned first in this column — “needle ice” is “where water-saturated soil is pushed up by needles of ice during nights when the temperature goes below freezing for much of the evening.”
Cheryl Kimball is a freelance writer who lives north of Rochester. You can email her at firstname.lastname@example.org.