"Most major droughts in the Corn Belt start in the fall," says Jim Newman, flatly. "If you don't get recharge down deep in the fall, you're not likely to get enough precipitation in the winter months, particularly in prairie areas, to catch up.
"The thing about fall recharge is that moisture can percolate down and get to the depths under the soil. The hybrids we have today that are more drought-tolerant have the roots that can go down that far to get it. But if we don't get it, then we start into next season short.
"The problem with spring rains, even if they are plentiful, is that we get runoff and evaporation and it's tougher to recharge the subsoil."
Newman, approaching his 90th birthday, is a retired climatologist from the Purdue University Agronomy Department. However, one of the things he studied closely was long-term weather events, and the events of moisture cycles, particularly in the Corn Belt.
Dev Niyogi, current Indiana state climatologist based at Purdue University, agrees that the drought is already serious in southern Indiana. He will watch northern areas, including Michigan and Wisconsin, this winter to see if it creeps down into northern Indiana and becomes more severe there as well.
Both climatologists point out that even if the Corn Belt sees a reasonable amount of snow, it doesn't amount to much help form a precipitation standpoint. "It takes 10 to 12 inches of snow to get an inch of precipitation," Niyogi says. "That won't help on recharge."
Newman agrees. Besides, some of the snow is lost to evaporation, and never makes it into the soil in the first place. That's another reason why snowfall is not the answer to recharge. It needs to happen in late fall if it's going to be effective and set up for a good crop in 2011, Newman says.
Unfortunately, that's not what Niyogi sees happening at the moment. Long-term forecasts and the presence of La Nina indicate that precipitation will likely be below normal through the winter. If the La Nina ends, although it's difficult to predict, rainfall could come up in March or April.
"The other factor contributing to this drought is the lack of hurricanes coming ashore during the tropical hurricane season," Niyogi says. "There were more tropical storms than normal, as predicted, but most went off into the ocean. We didn't get relief from a tropical storm reaching land as we have in the past."
While it's way too early to tell, Niyogi says drought risk is likely up for 2011. Part of it will depend upon how the accuracy of the forecast plays out through late fall and winter.