Nashville, Tenn. — A persistent arctic chill tightened its grip on the nation Wednesday and reached deep into the South, where it was blamed for at least six deaths and threatened to freeze crops and bring snow to places more accustomed to winter sunshine.



Authorities said four people in Tennessee, one in Mississippi and one in South Carolina have died from the cold since the weekend. They included a man with Alzheimer's who wandered out into his yard in Nashville and froze to death, and a homeless man found dead in a tent in South Carolina.



The total doesn't include people who died in car accidents on icy roads and in fires started by stoves and space heaters.



The deep freeze was expected to linger through the weekend. The National Weather Service predicted the heaviest snow from the fast-moving system would fall on Iowa, Missouri and Illinois, with 4-6 inches predicted along with some locally heavier amounts Wednesday afternoon through Thursday.



In a rare turn for the South, forecasters warned that snow and ice were possible Thursday from South Carolina to Louisiana and wind chills in the region could get down to near zero at night.



"This air mass originated on the ice cap at the top of the world," said Bobby Boyd, a weather service forecaster in Nashville. He said the cold shot wouldn't be spent until it plunged southeastward and moved well beyond Cuba into the Caribbean.



The frigid weather hampered northern firefighters and even made life hard for Florida's tree dwelling iguanas.



In Indianapolis, frozen hydrants frustrated firefighters as they tried to put out a Tuesday night blaze at a commercial building.



In central and south Florida, farmers were trying to salvage citrus and vegetable crops by spraying them in protective layers of ice and covering them in plastic.



It was so cold in Florida, freezing iguanas were seen falling out of trees. Experts say the cold-blooded reptiles become immobilized when the temperature falls into the 40s and they lose their grip on the tree.



Kentucky Gov. Steve Beshear has declared a state of emergency in Perry County, where water line breaks have left large swaths of the area without water.



Officials said the city of Des Moines is likely to exhaust the remainder of its $3 million annual snow removal budget with this week's storm, expected to dump up to as much as 10 inches of snow in some areas. That is on top of the more than 28 inches of snow that fell in December in the city.



In the Dakotas, Interstate 90 between Rapid City and Mitchell in South Dakota was closed Wednesday because of zero visibility that led to backed-up traffic and some crashes.



Police in Kansas City, Kan., said a man died Tuesday after jumping over an interstate highway barrier wall, apparently to escape sliding cars after he was involved in a multiple-vehicle crash. Officers said 35-year-old Verner David Estrada-Duran likely assumed level pavement was on the other side, but he ended up falling about 80 feet to his death.



Much of the Blue Ridge Parkway in North Carolina and Virginia has been closed to motorists because of heavy accumulations of snow and ice as well as downed trees.



In Maine, a pilot died Monday after he reported ice buildup on the wings of his small plane and it crashed into a river channel. Searchers were also looking for an 18-year-old snowmobiler who disappeared on New Year's Day. And in Wisconsin a 7-year-old boy died when he fell through ice into a river while sledding with friends.



In coastal North Carolina, volunteers were scrambling to save endangered sea turtles that were stunned by the cold and stranded off the Outer Banks.



Southern supermarkets were doing a brisk business in staples like bread and milk.



Ann Warden of Brentwood, Tenn., loaded eight grocery bags into the trunk of her black luxury car Wednesday morning and worried about a snowy forecast.



"You know Nashville gets paralyzed with just one snowflake," she said. "I couldn't be caught without milk. And I got some nice wine at the liquor store."