ATLANTA — Temperatures plunged well below freezing across Georgia Tuesday morning, prompting at least four school systems to close.

Schools in Liberty and Bryan County didn't restart classes today, but temperatures are expected to drop below freezing again tonight and Wednesday morning, when Bryan County students are expected to return to class. Liberty's students restart Thursday.

The National Weather Service in Peachtree City said a wind chill advisory in North Georgia continued through 10 a.m., as wind chill readings were expected to be as low as 2 degrees below zero.

The low wind chill was a result of extremely cold temperatures combining with strong winds. The wind chill alert was in effect for Fannin, Gilmer, Union, Towns, Pickens, Dawson, Lumpkin and White counties in north Georgia.

WXIA-TV reports that snow and ice on roads prompted officials in Rabun, Towns, Union and Gilmer counties to cancel classes Tuesday.

Shortly after 5 a.m. Tuesday, the weather service was reporting 21 degrees with light snow in Blairsville, in the north Georgia mountains.

Georgia Power reported that about 1,500 customers were without power early Tuesday, with many of them in the Macon, Columbus and Americus areas. Power had been restored to all but 700 customers by 8 a.m.

No problems were reported in Coastal Georgia, but residents are being advised to cover outdoor plants, bring in pets and drip faucets that are exposed to elements again tonight. The low is expected to be in the upper 20s near the coast and lower 20s further inland, including around Hinesville.

Temperatures start rising some Wednesday with overnight highs in the 30s. They should be in the mid 40s Friday night-Saturday, according to the National Weather Service.