We have highly unpredictable weather in Mississippi with temperatures that range from extremes below the zero mark and highs that rival western deserts. We have rainstorms that deliver double digit amounts in a few hours and hurricanes that devastate lives and property. Our frequency of tornadoes is almost as severe as Oklahoma or Kansas.

But sometimes we have something that is so unusual as to shock even the most seasoned meteorologists: We call it Mississippi snow.

A lot of farm offices have pictures that show a skier atop a field of open cotton, sometimes in front of a picker, with the caption “Ski Mississippi,” but we seldom see fields that qualify for this designation or this level of yield. This year I have seen several that from a distance a person unfamiliar with the crop might mistake for a scene from a northern winter.

The reference to a field of cotton as Mississippi snow will require a yield level of at least three bales per acre. But when the yield level passes this point the appearance of the field can become almost solid white, as in one field in which we had a variety trial last year that produced yields of over four weighed bales per acre. I have seen a few fields this year that approach this degree of density and whiteness, but I don’t yet have final yield reports to compare.

It is really amazing that we have been able to achieve these levels of cotton yield this year, especially given the fact that many people were earlier concerned that the crop was not receiving the necessary levels of heat unit accumulation needed for an above average crop. However there was at least one factor that was not mentioned. At least among those I have talked with about it, no one mentioned that cooler nights allowed cotton plants to direct almost all of their solar energy capture into seed and lint rather than into cooling the plants at night as is the case most years. The “dark respiration” factor is often overlooked, but this year has given evidence that it is likely more important than we have thought in the past.

Another big factor is that the crop in most cases received adequate rainfall to prevent moisture from limiting yield. Of course this interacts with temperature since transpiration levels are of necessity higher when temperatures are high.You might say that these two major weather factors worked together to allow cotton plants to approach their maximum yield potential.

Last year was also a high yield year for many growers, but the high yield pattern was more general this year, at least within the bounds of the area where I work. Other contributing factors have been lower insect pressure, fields that in most cases have been rotated from other crops, exceptional varieties, and excellent weed control.

Last week I saw four cotton harvesters in one field in Yazoo County. These were the latest technology of round bale harvesters which added up to something near three million dollars worth of machinery in one field. It’s amazing how far we have come since I was a kid with a cotton sack picking Mississippi snow with my grandfather. I wish he could see this.