The Mississippi, Missouri and other Midwestern rivers in Missouri and at least five other states have surged since torrential rains drenched the region over the past few days.
The weather service warned that sensitive plants could be damaged by the cold temperatures and frost, something Strawberry Hill Farms owner Steven Sapp is monitoring closely.
Columbia Regional Airport has measured more than 3 inches of rainfall since Sunday. If the river gets above 26 feet, pumping will begin at Hartsburg.
Drivers should avoid flooded roads because the depth and force of the water might not be evident, according to a release from Public Safety Joint Communications.
In the Plains and Midwest, seemingly every community was under some sort of watch or warning.
Heavy rain across the Midwest has eased drought conditions in some areas.
Public Safety Joint Communications activated warning sirens across Boone County shortly after 5:15 p.m. Wednesday in response to a tornado warning issued by the National Weather Service for the southeastern part of the county.
The National Weather Service has issued a tornado watch and a flash flood watch for Boone County.
As a large storm system passes through the area, Columbia residents can expect more precipitation and severe conditions.
Above-average snow cover and a chilly, wet spring have helped restore moisture to many states burdened by last year's drought.
Sanborn Field recorded 2.08 inches of rain Wednesday from the spring storm system that swept across Missouri.
Utility workers scrambled to restore power to more than 23,000 still-affected Missouri homes and businesses. Missouri Gov. Jay Nixon declared a state of emergency.
After temperatures in the 70s, the National Weather Service expects thunderstorms Wednesday and cooler temperatures later in the week.
The National Weather Service will provide media outlets and emergency services with more detail about the strength of a brewing tornado or thunderstorm, what it may hit and when.
The high Thursday in Columbia was 60 degrees, according to the National Weather Service. Temperatures in the upper 50s and lower 60s are expected Friday, Saturday and Sunday, with thunderstorms possible Saturday afternoon.
Temperatures have averaged 36.7 degrees this month, compared with an average of 43.6 degrees in the years since 1889. The last year the monthly average was that low was 1983.
The snowstorm was little more than a nuisance by the time it reached the East Coast. Air travel was the most affected, with nearly 600 flights canceled.
A meteorolgist with the National Weather Service said Columbia received 9.2 inches of total snow accumulation Sunday. Approximately 7 to 8 inches settled on the ground.
Forecasters with the National Weather Service in St. Louis said between 5 and 7 inches of snow have fallen in Boone County so far today. The heaviest accumulation has passed, and Columbia can expect to see a maximum of 2 additional inches of light snow and flurries for the remainder of the day.
The National Weather Service said parts of Colorado and northwest Kansas saw 10 to 15 inches of snow Saturday. Boone County had 7 inches by mid-morning Sunday.