It happened as temperatures rose above freezing and was observed at Greenland's Summit Station - more than 10-thousand 500 feet above sea level.
Walt Meier is Senior Research Scientist at the U.S. National Snow and Ice Data Center - and says it was a bit of a shock:
"I don't know exactly how much fell. One of the things there is that they have a weather station there but they hadn't really thought about rain because it just doesn't happen there. So they didn't have any rain gauges to measure it."
