Atlanta ice storm batters power grid. Why ice is worse than snow.

Atlanta ice storm took out power for more than 100,000 Georgians Wednesday. Officials warned outages could continue as the Atlanta ice storm brought down tree limbs and weighed on power lines.

An Atlanta ice storm dumped snow and ice on much of the South late Tuesday and into Wednesday, ensnarling traffic, shutting down businesses, and causing at least six reported fatalities. Officials issued dramatic warnings in which they described the Atlanta ice storm as "historic" and "catastrophic."

More than 100,000 Georgians were without power early Wednesday, according to Georgia Power, a utility that serves over 2 million customers in the state. Georgia Gov. Nathan Deal declared a state of emergency Monday and expanded it to cover 89 counties by Tuesday. President Obama joined in declaring an emergency in the state Tuesday. Reports across the South indicated nearly 140,000 without power. 

“My primary request to the president was for generators in the case of power outages," Mr. Deal said in a statement. "The federal declaration makes those available, but it also allows us to ask for other supplies, such as food, blankets and commodities, as needs develop.” 

The potential for power disruptions is large, officials said, as a quarter to three-quarters of an inch of ice is expected to coat the area in and around metropolitan Atlanta.

While snow or rain can blow off power lines, ice sticks tightly to transmission lines and freezes the wood poles and steel towers that hold them aloft. The added weight and rigidity makes them more likely to collapse, particularly in high winds. Frozen, falling tree branches also play a big role in taking out power lines.

Utilities have procedures for melting ice on power lines or breaking it off with special rollers, but that procedures typically require shutting down power to certain customers for one to three hours. It's unclear if utilities in southern states that are unaccustomed to ice storms would have such capabilities. 

The Atlanta ice storm comes on the heels of a series of winter storms that have battered much of the US since the beginning of the year. The prolonged spate of winter weather has driven up fuel prices, with customers in the Northeast paying record prices for natural gas and extremely tight supplies of propane across the US. Natural gas futures jumped 25 cents, or 5 percent, to $4.82 per 1,000 cubic feet Wednesday.

Natural gas and electricity are the predominant fuels used for heating in Georgia, according to 2009 data from the US Energy Information Administration, each making up 48 percent with propane and other fuels supplying the rest. 

"This is one of Mother Nature's worst kinds of storms that can be inflicted on the South," Georgia Gov. Nathan Deal told reporters Tuesday afternoon, as reported by CNN. "That is ice. It is our biggest enemy."