With the seemingly endless supply of moisture falling in Iowa over the last three weeks, it’s hard to believe the drought of 2012 could still be in effect. Rivers are fuller than they’ve been in at least two years and waterlogged soil is everywhere. So, why hasn’t this recent rash of rain brought the drought discussion to an end?
While the problem isn’t solved completely, the rains have eased the situation substantially. Our state climatologist, Harry Hillaker, noted the heaviest days of rain resulted in the wettest week of weather in terms of average statewide precipitation since June 2010.
When the extremely wet weather started in late March/early April, frozen soils in the northern part of the state were not able to take in all of the moisture—although soils have thawed and were able to start taking in rain last week—and as a result, most ran off into the rivers, causing flash flooding in some locations. Further south, where the soil had thawed, more moisture was taken in; however, with such large amounts coming at once, the soil could only hold so much before runoff occurred, much like a saturated sponge.
Regardless, a wide-ranging ‘one category’ improvement was implemented for most of our state, and the northeast part of the state received a ‘two category’ improvement. As a reminder, the drought categories range from D0 (abnormally dry) to D4 (drought – exceptional). The eastern third of Iowa is no longer in any drought category. Most of the middle third of the state is now classified as D0 or D1, with most of the western third as D1 or D2, with a very small area in the northwest part of the state at D3.
While the situation has improved since last fall and winter, we still need more rain before we are completely out of the woods. Hopefully it will come as less frequent, less total rainfall events that will allow the soil to properly absorb and maintain a moisture status that will benefit all of Iowa’s growers.