How frost forms and the impacts it can lead to
It's that time of the year when cooler mornings arrive, and overnight frosts/freezes become more likely. The first frost in Central Missouri is slightly behind schedule, though, as areas like Columbia typically experience this event by October 20th. Areas to the north, like Macon and Moberly, usually experience their first frost even earlier in the month.
Some areas had their first shot at a frost last night, but another frost advisory is in effect for areas like Audrain, Monroe, Randolph, Chariton, and Macon County until tomorrow morning. This is because temperatures will be dropping into the mid-30s overnight, leading to the best chance of a frost in those northern areas.
Even though Boone County was not under a frost watch last night, and the majority of the area saw temperatures in the upper 30s, some localized areas were still able to observe frost. These localized areas saw low temperatures at 32 degrees rather than the upper-30s. The main reason this occurred was due to the elevation difference. The temperature at Columbia Regional this morning was 39 degrees, while the temperature the viewer reported just a few miles away in an area that was 300 feet lower in elevation than the airport was at 32 degrees. Since colder air is denser, it tends to sink to the lowest-lying areas, leading to this temperature difference in such a localized area.
These temperatures at or below freezing are one of the main factors to observe frost. Frost typically occurs after a day when the sun has been heating the surface of the Earth. Once the sun sets, radiational cooling occurs. This is where the heat that has been gathered at the surface during the day rises, and this rising motion leads to a cooling of the air at the surface. Once the temperature at the surface reaches freezing or below freezing, the only thing that is left is for there to be a higher moisture content present. If the temperature at the surface is in proximity to the temperature when moisture forms, frost will begin to form.
This frost can lead to many different impacts. Plants that are sensitive to the cold or contain higher amounts of moisture can be damaged due to the frost, potentially freezing the water inside the plant cells. Similarly, crops that contain more moisture or need warmer conditions to thrive can be harmed or lost if they are not harvested before a frost or freeze arrives. Heavier frost conditions and freezes where temperatures fall well below freezing can have larger impacts. One of these impacts could be pipes freezing in your household overnight.
One of the ways you can prevent your plants from being damaged by an overnight frost is by covering them or bringing them inside if possible. On the frigid nights where a freeze is possible, let faucets lightly drip through the night and open cabinet doors to expose the pipes to warmer air.
