Frost flower

Frost flowers are ice crystals commonly found growing on young sea ice and thin lake ice in cold, calm conditions.
in October of last year, I observed this effect at frosts
https://www.google.ru/search?q=ice+flowers&newwindow=1&rlz=1C1ASRM_enRU654RU654&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjHurjwvc7OAhWE_ywKHdonCgwQ_AUICCgB&biw=1024&bih=705