Midwest Overview - June 2008
Record Rainfall and Record Flooding
June was a very wet month across a significant portion of the Midwest, with numerous heavy rain events that helped produce record flooding in Iowa, Wisconsin, Indiana, and Illinois. Precipitation was more than 200 percent of normal across much of Missouri, Iowa, southern Wisconsin, central Illinois, southern Indiana, central Ohio, and northern lower Michigan (Figure 1). Rainfall totals exceeded 12 inches in large portions of the region (Figure 2), with Martinsville, IN reporting a total of 20.11 inches of rain for the month. This more than doubled the old record of 9.47 inches in 1998. This is also the highest amount for any month in Martinsville, eclipsing the previous record of 13.71 inches in July 1992. Records for Martinsville date back to 1922.
Preliminary data indicate that 66 locations in the Midwest set new June rainfall records, and another 104 locations had rainfall totals that ranked second to fifth highest (Figure 3). In addition, this was the wettest January-June period on record for 106 locations in the Midwest, and the second to fifth wettest for another 180 locations (Figure 4).
While most attention was focused on the heavy rainfall during June, dryness persisted from southeastern Missouri east through southern Kentucky. Rainfall over southern Kentucky was less than 50 percent of normal for the month,
The wet first half of the year along with the record June rainfall caused devastating flooding in Iowa, Wisconsin, Indiana, Illinois, and Missouri and numerous flash floods in Missouri and Ohio. Persistent heavy rain resulted in record crests on the Cedar River in Iowa and many tributaries to the Mississippi River in eastern Iowa and southern Wisconsin (Figure 5). This resulted in record flooding on parts of the Mississippi River, even exceeding flood levels reached during the Great Flood of 1993 in some locations. At the end of June streamflows were still very high (Figure 6) and major flooding was still occurring in southern Wisconsin on the Rock River and major to moderate flooding was occurring along the Mississippi River from Quincy south to Chester. Details on the impacts of the flooding in the Midwest can be found in the weekly Climate Watch summaries.
Cool West, Warmer East
There was a strong northwest to southeast gradient in average temperature departures during June (Figure 7). Average temperatures ranged from 2°F to 5°F below normal in Minnesota to 2°F to 3°F above normal over eastern Ohio and western Kentucky.
Widespread Severe Weather
Severe thunderstorms peaked during June, and severe weather was reported in every state in the region (Figure 8), with the majority of the severe weather concentrated in the central portion of the region. There were 221 reports of tornadoes in the nine states during June (Figure 9), compared to only 119 in May. Four fatalities occurred at a Boy Scout camp near Blencoe, IA on June 11 when a strong EF2 tornado tore through the camp. Forty people were also injured.
For more details on weather and climate events during June 2008, click on the individual weekly report links on the upper right.