A winter storm warning has been issued for York and Chester counties beginning at 7 p.m. Tuesday, according to the National Weather Service.
The warning is in effect until 6 p.m. Thursday in York and Chester counties and until noon Thursday in Lancaster County.
The weather service says snow may begin falling locally earlier Tuesday and become heavier early Wednesday morning. Some sleet could be mixed in with the snow.
The warnings are being issued because of a wintry blast that will affect the western portions of North Carolina and South Carolina and parts of Georgia.
The weather service said that the combination of snow, "significant sleet" and freezing rain will make driving "treacherous" and create power outages.
Late Monday afternoon, the National Weather Service said predicted 5.9 inches of snow would fall in the Rock Hill area. Eight inches are forecast for Charlotte.
The watch is in effect from 6 a.m. Tuesday until 7 a.m. Thursday. The National Weather Service announced on Monday afternoon that Lancaster County was under a "winter storm warning" until 7 p.m. Thursday.
The state Department of Transportation has begun spreading brine on I-77 in anticipation of the storm, according to The Herald's news partner, WSOC-TV.
Across South Carolina, state transportation officials have about 2,500 employees ready to work if bad weather hits. By midday Monday, SCDOT had used more than 22,000 tons of salt and more than 16,500 tons of sand on roads. Additionally, more than 241,000 gallons of salt brine and more than 116,000 gallons of calcium chloride had been used.
The National Weather Service released a statement early Monday warning that light snow and sleet might descend on the Upstate region starting Tuesday. That snowfall will become heavier by Wednesday and mix in with sleet and freezing rain south of the Interstate 85 corridor.
At least 2 to 4 inches of snow may fall on the region, according to the statement. Forecasts for Rock Hill predict a 70 percent chance of snow Tuesday, while Lancaster has a 60 percent chance of snow and sleet Tuesday, and Chester a 70 percent chance. Temperatures for the next several days will range in the upper 20s and lower 30s with wind gusts reaching up to 25 mph.
The latest winter blast comes from the combination of cold air building north from Canada and returning low-pressure moisture from the northern Gulf of Mexico, forecasters say, bringing snow, sleet and freezing rains crashing down on the Carolinas and Georgia. Snow fell in the same areas two weeks ago, the result of an arctic cold front that moved through the region to the coast.
There is better (computer) model consensus, pointing to the main period of significant wintry weather occurring Tuesday night into Wednesday night, said Harry Gerapetritis, of the National Weather Service office in Greer.
Gerapetritis said Monday morning current indications are that the immediate Charlotte area will get 4 to 6 inches of snow, plus a considerable amount of sleet and some freezing rain.
He said an extended period of freezing rain, probably enough to cause widespread power problems, is likely for the corridor across Chester, York, and Lancaster counties.
However, Gerapetritis added, it will be another 24 hours before meteorologists have a good idea on the track of Wednesdays low pressure system. The heaviest precipitation is expected near the center of the low pressure system, and areas very near the center are most likely to see heavy amounts of freezing rain.
If the storm is as severe as meteorologist expect, it could take York County at least a week to recover, said Cotton Howell, director of York County's office of emergency management.
Howell said his primary concern is the effect the ice can have on trees and power lines. Heavy snow, he said, can weigh the trees down so that they tumble, taking down power lines with them.
In December 2002, more than 70,000 customers In York, Chester, and Lancaster counties were without power for up to several days after an ice storm. The damage was so severe that a Presidential disaster declaration was later issued.
Officials with both Duke Energy and York Electric Cooperative said that right-of-way limb removal is done throughout the year in anticipation of severe weather events. Duke Energy serves more than 65,000 customers in York, Chester, and Lancaster counties, and York Electric Cooperative services more than 46,000 customers.
Services that assist special needs populations were already planning on Monday afternoon for the potential disruptions caused by icy roads, and have prepared staff to be self-sufficient. The York County Board of Disabilities and Special Needs has more than a thousand clients, including hundreds who live in 26 residential group homes.
The staff at those homes are prepared to stay overnight Tuesday night and thereafter with the clients if travel becomes impossible, said Mary Poole, executive director for the disabilities board. More, those homes are stocked with emergency food and medical supplies, Poole said.
"We have an emergency plan in place for all our locations that will make sure all the people we serve are cared for," Poole said.
In Lancaster County, emergency officials said Monday that shelters will be open to anyone who loses power or heat during the winter weather event. Directions to available shelter will be available by calling 803-283-4136.
Lancaster officials also provided the following tips for dealing with the potential dangerous conditions:
Make sure you have sufficient heating fuel such as propane, fuel oil or wood.
Allow faucets to drip a little during cold weather to avoid freezing. Running water, even at a trickle, helps prevent pipes from freezing.
Make sure to have adequate food and other supplies that will be needed throughout the duration of the event.
Listen to a NOAA Weather Radio or other local news channels for critical information from the National Weather Service (NWS). Be alert to changing weather conditions.
Check smoke and carbon monoxide detectors. House fires pose an additional risk, as more people turn to alternate heating sources without taking the necessary safety precautions. A space heater should be plugged into a wall outlet instead of an extension cord. Follow manufacturers guidelines for proper clearance around any heat sources.
Bring pets inside during winter weather. Move other animals or livestock to sheltered areas with non-frozen drinking water.
The storm is not expected to hit the entire state, so electric cooperatives from other parts of the state that likely will not be affected are on stand-by to come to York County if needed, said Marc Howie, York co-op vice-president.
This week's winter storm watch goes into effect Tuesday morning and will last until Thursday morning. The watch means there is a potential for significant snow, sleet or ice accumulations that might impact travel.
The Charlotte Observer contributed