Tue October 30, 2012
A Morphing Storm: As Sandy Moves Inland, Snow And Winds Follow
Even though Sandy has switched from hurricane to post-tropical cyclone, it's still a formidable storm. The latest forecast predicts strong winds and coastal storm surges up to four feet in some places. Areas from the eastern Great Lakes region to the mid-Atlantic and up to southern New England can also expect an additional inch of rain.
And NPR's Dan Charles reports from Beckley, W. Va., that there's at least a foot of snow on the ground there, and more on the way.
The mid-Atlantic region is no stranger to hurricanes, but as Sandy made its way north and onto land, it became far more wintery.
Hurricanes draw their power and energy from the heat of ocean water, releasing it high in the atmosphere. It's this transport of heat that keeps the system spinning in the characteristic counter-clockwise direction.
As Sandy moved north and turned westward toward land, it collided with cold air making its way south from Canada. The huge, rotating storm began drawing this cold air into its cyclonic path, driving it farther south. That's why we're now seeing snow in places like Ohio, Kentucky, Virginia and West Virginia.
The National Weather Service points out that winter storms can spin around like a hurricane does, but there's a key difference between a wintertime cyclone and a hurricane (one type of tropical cyclone). Winter cyclones draw their energy from differences in temperature and pressure in the atmosphere, not from ocean heat.
What continues to make Sandy so powerful is its broad diameter — more than 1,000 miles — and its union with the winter storm descending from Canada.
Blizzard warnings remain in effect in the higher elevations of the central Appalachians. Charles reports the heavy, wet snow is breaking tree branches and downing power lines as wind gusts up to 45 miles per hour continue to lash the region.