William M. Welch

USA TODAY

The icy, snowy weather pummeling the South is expected to take a heavy toll on the region's plentiful trees.

"It's not unreasonable to expect that Atlanta — sometimes known as 'the city in a forest' — could lose a quarter of its trees in this storm," said meteorologist Eric Holthaus of Slate.

The heavy weight of ice accumulating on limbs can break apart and pull down trees, taking power lines with them as they fall to the ground, sometimes striking homes and cars and causing other damage.

"I think three-quarters of an inch of ice anywhere would be catastrophic," National Weather Service meteorologist Eli Jacks said.

Atlanta and much of the South are particularly vulnerable because there are so many trees and limbs hanging over power lines. When the ice builds up on them, limbs snap and fall, knocking out power.

"There is no doubt that this is one of Mother Nature's worst kinds of storms that can be inflicted on the South, and that is ice. It is our biggest enemy," Gov. Nathan Deal said.