We got our first frost flowers (hair ice) of the year on Friday. It is rare for us to get them before December: it requires a very specific combination of sodden sticks and cold.
These frost formations grow from alder sticks. The fine strands extrude from the stick as the surface freezes, so they truly do grow in a very similar way to hair.
I waffle between “frost flower” and “hair ice”; my current understanding is that the terms are semi interchangeable, and are more based on the type of formation than the actual process.
I admit I find “frost flower” a very appealing term, but this photo is definitely more on the “hair ice” part of the formation spectrum!
I periodically do posts of frost flowers/hair ice, since we’re fortunate enough to get them a few times each winter. Check for tags “hair ice” or “frost flowers” to find them!
After an unusually mild January, we just started a bit of a cold snap. That means hair ice (frost flowers)!
Larger sticks can “grow” longer hair ice, but small sticks sometimes have especially pretty formations — especially if it wasn’t especially cold. This was a fairly small stick.
This is a much larger stick — really a branch, maybe 3-4″ diameter. The length of frost grown is comparable in this case, but the result isn’t as spectacular.
However, it shows off the way the frost grows quite nicely!
Sometimes the tiniest sticks produce the prettiest formations — because you can actually see them!
In a big, fluffy formation, it can be hard to see the individual strands of frost.
This formation is on a tiny stick at the side of the driveway.
By contrast, here’s a frost flower that looks like a piece of cotton wool. It’s neat, but also hard to see enough detail to truly appreciate it.
I’ll close out with one that puts the “hair” in “hair ice”. They really do look like powdered ringlets! That’s because as the ice grows, it has a slight curve in one direction, resulting in a curl 🙂
We’re lucky enough to live in a region that gets frost flowers (hair ice) several times each winter.
On the morning of the solstice, for the first time we had both frost flowers and snow. I was initially disappointed, because I expected the snow to ruin the frost flowers, but it was a very light dusting of cold, small flakes — so it actually added an interesting dimension to the frost flowers.
Closeup of hair ice holding a perfect snowflake.
Frost flowers (hair ice) form when there are sodden sticks that dip below freezing overnight. Around here, the sweet spot is ~28-31 F. It needs to be cold enough to produce frost, but not so cold as to freeze the stick solid.
The ice forms on the surface of the stick, and is extruded as it freezes to form “hair” which can take beautiful forms that look like silvery locks or silvery flowers.
Characteristic hair ice formation
There is a fungal association with Exidiopsis effusa. Around here, there is also a clear preference for alder twigs and branches. I’m not sure whether that’s what the fungus prefers, or whether the wood somehow favors frost flower formation.
Frost flower and hair ice are two terms used semi-interchangeably. As far as I can tell, the distinction is mostly based on the type of formation. If it’s a burst formation (e.g. from the end of a stick), it’s a frost flower. If it looks like hair growing out of the middle of a stick, it’s hair ice. Even though most of what we get is probably more hair ice than frost flowers, I like the latter term better 🙂
Frost flowers and hair ice are relatively rare worldwide. They require specific conditions to “grow”. In climates with cold winters, you might be lucky enough to see a few in the autumns.
Here in the Puget Sound area, the winters are mild and tend to only dip below freezing occasionally. We also have an abundance of alders. That gives us the ideal conditions for hair ice and frost flowers.
Frost flower in the wild
To see them, go out on a cold morning and check any local alder groves. They tend to be more common at the edges of alder groves, where the sticks are a bit more exposed… but that depends on the temperature range. On a very cold morning (25-28F) there may be such formations deeper in the woods.
They are most common on mid-sized twigs and branches (~1/2-2″ diameter), but occasionally they grow on larger or smaller branches.
