Cold waves happen when the jet stream greatly amplifies from north to south.This allows frigid air from frozen arctic regions to rush southward into theUnited States.

The monster cold wave that hit the country in February 1899 was perhaps theworst in the memory of man. Then subzero temperatures occurred in every stateeast of the Continental Divide including Florida. In Tallahassee, thetemperature dropped to 2 below zero on Feb. 11 which is the only instance of asubzero temperature in Florida. Across the central and northern Plains,temperatures between 30 and 40 below zero were quite common. In Montana,readings were as low as 60 below! The 1899 blast triggered an incredible blizzard from the Gulf of Mexico to NewEngland during Feb. 12 and 13. Snowfall from Virginia to southern New Englandaveraged 18 to 30 inches. The deepest snow fell through the mid-Atlantic. InCape May, N.J., 34 inches of snow fell which remains the record for the entirestate.

The storm caused snow as far south as Tampa and Fort Myers, Fla., and northerncounties of the state had as much as 4 inches.

And how about this startling fact: It was so cold across the Deep South thatthe port of New Orleans, La., was completely iced over by Feb. 13. Furthermore,the Mississippi River froze its entire length all the way to the Gulf ofMexico.

Story by AccuWeather.com Senior Meteorologist John Kocet.