During the recent Arctic freeze in the United States Midwest, the temperature in the town of Sparta, Michigan dropped to -23 degrees Celsius by night and stayed below -15C even by day.

Sparta grows good apples in orchards to the west of town, but the few left on the trees in early February froze solid and were then coated with glaze ice.

Then a most curious event happened – as the thaw set in, “It was just cold enough that the ice covering the apple hadn’t melted yet, but it was warm enough that the apple inside turned to complete mush,” grower Andrew Sietsema told Reuters news agency.

As he shook the tree to prune it, the formerly frozen mush fell out of the bottom of the ice coats. This left trees with hollow ice apples still hanging from the branches.

Sietsema said he had never seen anything like this before and added that the “ghost apples” appeared in an orchard block of Jonagold, Honeycrisp and Gala trees that he planted in 2014.