Is this a flash drought?
The month of August slaughtered corn and soybeans around the country. Just a fraction of the normal rain amount fell in some key states for those crops, and now weather-watchers, farmers, and others are talking about the "flash drought" of late last month and so far in September and what it could be doing to what crop potential remains out in the field.
The latest update from the U.S. Drought Monitor shows the western and northwestern Corn Belt has incurred the most drought pressure in the last few weeks; around one-third of Iowa is now rated in severe drought, while growing portions of Minnesota, Wisconsin, northern Illinois, and northern Missouri are starting to feel increasing drought pressure.
A weather expert in that last state says the flash drought of the last few weeks is much different than last year's drought; last year saw the weather pressuring the entire nation's crops. This year's flash drought or "drought on steroids," on the other hand, is more localized and exerting more crop strain in a shorter period of time, says University of Missouri Extension climatologist Pat Guinan.
"Last year the drought covered much of the central United States. And it lasted longer. In the 2012 growing season, we saw unusual numbers of cloudless days. Lack of rain and high heat brought low humidity, which increased evapotranspiration. Plants soon sucked water out of the soil," Guinan says in a university report, adding the disparity between different parts of his state are immense. "In two hours, we can drive from areas reporting their wettest or their driest Augusts on record."
It's not just the short time frame that makes this year's conditions a flash drought. The overall dryness has combined with high relative overnight temperatures to make it easy for the mercury to climb during the day, making it easy for conditions to escalate to drought status quickly, says senior ag meteorologist with MDA Weather Services, Don Keeney.
"The precipitation-percent-of-normal map for the past month (see below) shows that the flash drought is indeed a reality," he says. "The warm temperatures are also helping to boost daytime high temperatures, much as it did last year."
But others say the flash drought is likely not just because of the recent heat and dryness. Instead, the latest named weather phenomenon is less of a specifically timed anomaly and more a function of the conditions throughout the growing season, says Agriculture.com Marketing Talk senior contributor and weather analyst jennys_mn.
"The main reason for this 'flash drought' is what many of us have eluded to all summer long: A plant root system that simply could not sustain the plant as the water stopped, which was a direct result of how this crop went in the ground," she says. "[That] was why a 14-billion-bushel corn crop -- in my opinion -- was not ever achievable. The only way it could've happened would've been a near-perfect growing season over the bulk of the Midwest with timely rains that actually happened, but of course didn't."
Another function of the flash drought beyond its effects on the quality -- or lack thereof -- of the crop is in how it proceeds toward harvest. Some say there are signs it's moving the crop toward maturity quicker than normal, while others say that's only true in specific areas, if at all.
"Maturity is advancing slowly (which is a good sign that the flash drought is not pushing maturity much)," says Agriculture.com market analyst Ray Grabanski. "We are probably no more than one week behind normal development for the crop as a whole, and we have warm conditions forecast for the next two weeks that will take much of the crop to maturity."
Adds MDA's Keeney: "I think the dry and warm conditions are helping to speed crop growth along, but not to the extent that some say it is. I am a bit surprised that it actually isn’t maturing the crop more than it is. But since corn is highly dependent on GDDs, and they have been elevated here of late, it has to be pushing the corn along some."
At least in the areas where the flash drought is more prominent, like south-central Iowa, it's clear the latest spurt of heat and dryness is providing the incentive for farmers to get in the combine.
"We are taking corn up to 28% on a half rate moisture scale, so expect to see an increasing amount of harvest activity through the week," says Cargill senior grain merchandiser in Eddyville, Iowa, Ray Jenkins. "I expect the week of September 16 will be quite active as folks try to capture the new-crop basis opportunities. This heat spell brought the crop forward five to 10 days pretty easily."