Crystal shells

A searing south-easterly gale set our rusty corrugated roofs rattling while the witches' knickers (more like a tattered ballgown), covering the farmer's straw bales, crackled and billowed above them.

I didn't expect to see anything of note on a short dog walk but was captivated by these ever-so-fragile flakes of ice here and there on the ground beneath the trees. I touched one and it crumbled and dissolved. I realised that they were the casings of ice that had formed on smooth tree trunks and then fallen, impressed with  patterns of the bark.

Has anyone else spotted them? It seems the poet Robert Frost (so well named!) had when he wrote:   

When I see birches bend to left and right
Across the lines of straighter darker trees,
I like to think some boy's been swinging them.
But swinging doesn't bend them down to stay
As ice-storms do. Often you must have seen them
Loaded with ice a sunny winter morning
After a rain. They click upon themselves
As the breeze rises, and turn many-colored
As the stir cracks and crazes their enamel.
Soon the sun's warmth makes them shed crystal shells
Shattering and avalanching on the snow-crust—
Such heaps of broken glass to sweep away
You'd think the inner dome of heaven had fallen.

It's part of a longer poem called Birches. 
We have no birches here, nor an ice storm of the magnitude he describes, but it was exciting to discover a new natural phenomenon