I asked, #mastodon answered...
https://fediscience.org/@Ruth_Mottram/111705895236414782
Ruth_Mottram - Ok mastodon, (or at least the part of it currently going through a big freeze), show me your strange ice pictures, your weird ice spikes, needle ice, hair ice and frazil ice, your beautiful ice crystals.
Is #icetodon a thing yet? It should be. I'll start.
#NeedleIce in the park today.. typically forms.when ground is warm (above zero) and air temperature cold (well below zero).