(cnn) for the first time on record, precipitation on saturday at the summit of greenland — roughly two miles above sea level — fell as rain and not snow.  temperatures at the greenland summit over the weekend rose above freezing for the third time in less than a decade. the warm air fueled an extreme rain event that dumped 7 billion tons of water on the ice sheet, enough to fill the reflecting pool at the national mall in washington, dc, nearly 250,000 times.  it was the heaviest rainfall on the ice sheet since record keeping began in 1950, according to the national snow and ice data center , and the amount of ice mass lost on sunday was seven times higher than the daily average for this time of year.  ted scambos, a senior research scientist at the national snow and ice data center at the university of colorado, said this is evidence greenland is warming rapidly.  "what is going on is not simply a warm decade or two in a wandering climate pattern," scambos told cnn. "this is unprecedented."  read more
rain fell at the normally snowy summit of greenland for the first time on record