MIAMI (AFP) – A sharp Arctic front sweeping the United States brought unusual snow to many of the deep southern states Saturday, and leaving normally balmy Florida shivering from record icy lows.

At least nine deaths were blamed on the freezing snap that blanketed much of the central part of the country this week, CNN said.

In sub-tropical Florida, Key West -- the southernmost point in the continental United States -- saw it's coldest day in 112 years, with a low of 47 degrees Fahrenheit (8.3 degrees Celsius).

The cold air was expected to settle over the state through the weekend with freezing temperatures set to remain until Monday.

The National Weather Service (NWS) also issued severe wind chill alerts for the Midwest, warning that even limited exposure to the cold could cause frostbite or hypothermia.

The Arctic air mass across the central states was bringing wind chills below minus 20 degrees Fahrenheit (-28 degrees Celsius) as officials said the conditions could mean frostbite in less than 30 minutes.

"Those planning to venture outdoors would use common sense and dress warmly," the National Weather Service said, urging people to make sure all exposed skin is covered.

Florida's citrus growers were on alert to protect crops in their key 9.3-billion-dollar-a-year industry, which many have feared could be hit hard by the unusual freezing.

Financial analysts warned there may be a far-reaching impact of the cold front on the fruit's market value as farmers scrambled to avert a ruined harvest.

The state's tropical animals too have been affected by the cold snap, with wildlife officials going so far as issuing advisories on how to save frozen iguanas.

The lizards become completely immobile in temperatures below 40 degrees Fahrenheit (four degrees Celsius) as their cold blood stops flowing, and have been filmed this week falling out of perches in trees.

Residents are advised to place the rigid lizards in sunlight where they can revive in warmth.