1957, July 30: Edwin Groff's Ice Fall
On July 30, 1957, Edwin Groff, a farmer from Reading, Pennsylvania, heard a whistling sound just moments before a huge piece of ice hit the ground just a short distance from where he stood. The chunk was about two feet across and weighed around fifty pounds. He called his wife to look at it, and as they were examining the first a second, slightly smaller, chunk of ice also came whistling down.
A meteorologist declared it to be natural ice that had been formed and carried by the jet stream high up in the atmosphere. This theory was later abandoned when it was noted that the jet stream could not carry chunks of ice in mid-air.
At the moment I have just one source for this account -- Frank Edwards' factually challenged Stranger Than Science (1959) -- so it is marked both as 'needs investigation' and 'unreliable'. I will update this account as I have time!