Now termed the Great Flood of 1993, the flooding that occurred along the Mississippi and Missouri rivers in April and May of that year was epic. Covering nine states and 400,000 square miles, it was the most costly natural disaster ever in the U.S. at the time, incurring $37 billion in damages*. It’s compared to the Great Flood of 1951, and the Great Flood of 1844 – but the 1993 flood levels were higher than in all previous floods although damage was mitigated in part by levee improvements after the 1951 disaster.
2019: Another great flood and the wettest season on record
Fast forward almost 30 years to 2019. The year began with the wettest January – August period on record for the U.S., and is now on track to record one of the shortest growing seasons in history. What does this mean for final corn production, and can the 1993 year shed any light on this question? Let’s take a look.
What did the flood mean for corn production, in 1993?
The 1993 season produced 6.3B bushels of corn, which was 35% less than the 2-year production average of the preceding and following years (1992 and 1994). The combination of decreased yield (-25%) and harvested area (-13%) were to blame. Total production value for the 1993 corn crop was $16B – a reduction of $6B from the 1992 and 1994 seasons’ average value of $22B.
And what was the downward revision in 1994, as a result of the flood?
For grain traders and growers planning to market their corn crop, the real story lies in the difference between yield estimates in the September 1993 USDA crop report and the final yield numbers reported in early 1994. In September of 1993, USDA projected corn production at 7.2B bushels, but the final production number for 1993 was significantly lower, at >6.34B bushels.
This reduction equates to a 14% downward revision in total corn production, mostly due to a decrease in actual yields. In fact, the size of this downward revision is the biggest percentage drop in the 54 years the USDA has been tracking corn production (see table below).
What to expect in 2020, after another great flood.
In this historic flood year, so similar to 1993, it’s worth considering the past as prologue during the final days of the growing season. Why? Because the USDA yield estimation methods do not fully capture the devasting effects on yields from flooding and waterlogged soils., especially due to uneven stands and below optimal plant populations, increased weed competition, and N deficiency from loss of applied fertilizer nitrogen. So buckle up for what may be a bumpy ride!
*$15 billion in 1993 dollars
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