Today marks the 30th anniversary of a weather event which caused significant damage to agriculture across the Southeast as well as many other problems. A major cold outbreak spread over the Eastern US, extending all the way down into Florida. It caused at least 126 deaths and killed off 90 percent of the citrus crop in Florida (including almost every citrus tree in central Florida), leading it to be called the “freeze of the century”. President Reagan’s second public inauguration was scheduled to be held outside that day, but due to the extreme cold was moved inside the Capitol building.
The State Climatology Office of North Carolina has provided an excellent blog posting on the causes of this destructive weather event (https://nc-climate.ncsu.edu/climateblog?id=118&h=5666e5c1). Some additional information is available from the National Weather Service Office Newport/Morehead City at https://www.erh.noaa.gov/mhx//EventReviews/19850121/19850121.php. The losses to the citrus industry were estimated at $1.2 billion in 1985 dollars.
Wikipedia even has an article on this extreme event at https://en.wikipedia.org/wiki/Winter_1985_cold_wave.