Was that really snow in South Florida? No, experts say, it was ’graupel’
Videos on social media purport to show snow in West Palm Beach around 1:45 p.m. when the temperature at Palm Beach International Airport was 57 degrees.
National Weather Service meteorologist Ariel Cohen said temperatures were “far too warm to support snowfall anywhere across South Florida.”
Instead, Cohen said what people saw is called “graupel” — small, soft ice particles similar to mushy hail.
Cohen said the cold air overlying the warm Gulf Stream waters caused surface air to rush high into icy layers in the atmosphere — similar to the process that creates hail during summer thunderstorms.
The graupel developed far above the surface of the Earth and was blown with misty rain southwestward onto the coast producing light showers with some graupel that was able to maintain its shape as it fell.
“Bottom line point here, there is no snow anywhere across South Florida,” Cohen said.
While it might not have snowed Wednesday, it did on Jan. 19, 1977.
The snow that day 43 years ago had an icy reach as far south as Homestead Air Force Base — the farthest south snow has been recorded in the contiguous U.S. It spread east to Freeport on the island of Grand Bahama, which is the only instance of snow being observed in the history of the Bahamas, according to the Florida climate Center.
Previous to Jan. 19, 1977, the farthest south snow had been seen was along a line from Fort Myers to Fort Pierce in February 1899, according to the National Weather Service in Miami.
Climatologically, it is not supposed to snow in South Florida. The laid-back tropics are a region constantly gaining energy from the sun, and with Florida’s temperatures moderated by warm water on three sides, snow is unusual even in northern reaches of the state.
But in January 1977, all the ingredients for frozen precipitation came together. The high pressure near California forced a mountainous ridge into Canada and a deep trough to dig through Florida, which funneled arctic air south. While winds at the surface were blowing from the north behind the cold front, winds high in the atmosphere at 5,000 feet were out of the west. That westerly wind picked up moisture from the Gulf.
At the same time, the freezing level in the atmosphere was at 1,500 feet above sea level, which is low for South Florida and kept the snow from melting before it hit the ground.
This story originally published to palmbeachpost.com, and was shared to other Florida newspapers in the new Gannett Media network.