The phenomenon was formed after the freezing rain.
On February 6, Andrew Sietsema sent photos of icy hollow apples to WoodTV . He took pictures while cutting branches from fruit trees.
Andrew explains the phenomenon in the following way: after a rain, a hard shell formed on the rotting fruit. The temperature was perfect — too cold for the ice to melt, but warm enough for the apples to rot, and the flesh to flow out from below.