S.A. Weather and Disaster Information Service, South Africa .

Weather Rarity: Snow in 49USA States

(Click on image for larger view. Get out the toboggans and winter gloves: There's snow on the land in 49 out of 50 U.S. states - including Hawaii. The sole say that isn't at least partially a winter wonderland today is Florida, according to the National Weather Service (NWS). The agency estimates that 70.

percent of the area is currently covered by snow. [Read: What Are the Chances of a White Christmas Everywhere?] "It's not typical," NWS public affairs officer James Peronto told LiveScience. The National Operational Hydrologic Remote Sensing Center, which tracks snowfall, doesn't keep statistics on the ordinary snow cover, Peronto said. However, in December, an average of 35 percent of the United States had snow on the ground. Unusual Southern Storm Snow in the Rocky Mountain states and Northeast is the average in winter, of course. Even Hawaii often sees snowfall at high elevations. Right now, the top of the dormant volcano Mauna Kea on the island of Hawai'i is covered with 7 inches (18 centimeters) of snow. What's unusual about now is the winter storm that passed through the Southeast, Peronto said. "The Southern states don't typically get significant snow amounts through the year," Peronto said. "It takes a particular form of weather scenario to provide that to happen." In this case, moisture from the Gulf of Mexico met up with cold air parked over the South. The result: Ice, sleet and lot of the white stuff. Snow in the eastern third of the United States is particularly unusual this class because La Nina (unusually cold ocean temperatures in the Pacific near the equator) normally keeps the jet stream in the northern regions of the United States, said David Robinson, the state climatologist of New Jersey and a professor at Rutgers University. But recently, the La Nina effect has been overshadowed by a negative North Atlantic Oscillation, an atmospheric pattern that brings cold and c to the East and Southeast. "If the North Atlantic Oscillation was what we call neutral or positive, we might make our lounge chairs out today," Robinson told LiveScience. [Read Q&A with Robinson About Wild Winter Weather] Snow over time Snow in so many states is "not an every-winter event," Robinson said, though the final sentence it snowed in all 50 states was last February. Before that, he said, you take to go backwards to the seventies to find winters where snow fell across so often of the North American continent. "The sizing of the United States is such that when the jet stream dips down in the orient and brings a lot of dusty air and c to do it downwards into Ga and South Carolina, it bulges up in the west," Robinson said. That usually keeps snowy conditions out of places like Texas while it's also snowing in the Deep South. On his website, Robinson tracks daily divergence from average snowfall. The map for Jan. 11 shows a large belt of above-average areas. Robinson's research hasn't turned up any long-term changes in winter-snow cover in the United States over the last 40 years. But spring-snow cover is decreasing, he said. "Last winter, we had a record extent of snow cover over North America, and last spring was a record low extent [of snow cover]," Robinson said. "So we went from one extreme to another." - OurAmazingPlanet