|Drought Potential Briefing - April 17, 2000
State Climatology Office - DNR Waters
Minnesota enters the growing season on the heels of a dry autumn and a snow-scarce winter. Many of the state's hydrological systems are showing the signs of precipitation deficits. These deficits leave Minnesota's water resources very dependent on adequate spring rains.
The last quarter of 1999 (October - December) was extremely dry across most of Minnesota. Many western Minnesota communities were at or near all-time record low precipitation totals for the period. Additionally, snowfall totals this past winter were very light, roughly 50 to 75 percent of average. The shortage of precipitation created deficits in surface hydrology normally benefiting from autumn recharge and snow melt runoff. Topsoil moisture in many areas is short, flow in many Minnesota streams and rivers is low, and some wetlands are without standing water. (Ironically, there are areas of northwestern and north central Minnesota that have welcomed the dry weather, as it has helped to alleviate high water problems caused by the extraordinarily wet decade of the 1990s.)
The situation is most acute in far southwestern Minnesota where the dry spell commenced in July - 1999, roughly three months earlier than the rest of the state. Precipitation totals over the past nine months have fallen short of normal by over eight inches in some of these areas. The National Drought Mitigation Center classifies southwestern Minnesota, along with portions of Iowa and Nebraska, in the "Severe Drought" category. In these areas, soil moisture is deficient throughout the rooting zone and stream flows are far below median levels.
Precipitation patterns over the next two weeks could set the tone for the coming growing season. Should Minnesota not receive near to above-normal April precipitation, the situation could deteriorate quickly. A return to near-normal precipitation totals would ease the concerns of the agricultural community, but would not change the surface hydrology significantly. To compensate for the precipitation shortfalls, above-normal precipitation is needed to refill wetland complexes and increase stream flows.
It is premature to declare an imminent state-wide drought, however the situation in far southwestern Minnesota is serious and warrants attention. Elsewhere across the state, public and private entities should take the proactive step of reacquainting themselves with their drought contingency plans.
It is important to note that drought should not be considered an aberration, but rather treated as an inherent component of a continental climate. For many communities, the 1990s were the wettest decade of the 20th Century, thus the current water deficits are magnified by comparison with the recent past.