A Fallstreak hole was photographed by a number of IWO followers during Wednesday (30 December, 2020).
Debbie O'Callaghan captured this photo of the relatively rare meteorological phenomenon from Dublin's Phoenix Par.
This feature forms in clouds of supercooled water droplets (sub 0 °C but not frozen). Ice crystals introduced to the cloud grow at the expense of the droplets, and fall from the cloud producing the 'hole' feature.