Temperature and Precipitation Anomalies.
The Midwest experienced its 42nd wettest June on record. However, unlike during the spring season, the precipitation was not widespread, but was concentrated in Minnesota, Wisconsin, and smaller portions of Illinois and the Ohio Valley (Figure 1). Some locations in northwestern Minnesota received over 12 inches of rain in a matter of days early in June, exceeding 200% of normal precipitation for the month (Figure 2). This concentration of moisture caused damaging floods in northern Minnesota (9th wettest June), where agricultural losses top $370 M, and the town of Roseau was completely inundated, with damage estimates approaching $100 M. Later in the month, 7-10 inches of rain fell in southeastern Minnesota and western Wisconsin, causing more localized flash flooding. Despite these damaging flood situations, most of the Midwest was actually below normal in precipitation during June. Temperatures were 2.1-3.2°F above normal in all states, with the Midwest having its 17th warmest June (Figure 3). Minnesota was the most warm compared to normal, and had its 10th warmest June despite the rains. At the same time western Iowa and northwestern Missouri soils became quite below normal in soil moisture, leading to abnormally dry conditions entering the Midwest once again at the end of the month (Figure 4, National Drought Mitigation Center - NDMC). Other portions of the central Midwest also missed much of the late-month rain, and are drying considerably, including a band from central Illinois to southern Michigan.

 

Extreme Events and Impacts.

Major Flooding near the Illinois-Wisconsin-Iowa Junction, June 3-4.
Heavy rain fell in eastern Kentucky on June 1-2, causing local flash flooding, but the primary rain-producing system for the period arrived on the 3rd. A series of upper air short waves passed over the top of the ridge in the jet stream and generated several mesoscale convective systems, large clusters of thunderstorms bringing some severe weather and copious amounts of rain. The cold signatures of merged anvils covering diameters of more than 100 miles in southern Wisconsin were seen in the infrared satellite imagery during the overnight period (Figure 36, U of Illinois Dept. Of Atmospheric Science - UIUC DAS). At the same time, the leading edge of storms was capable of severe wind and hail (Figure 37, UIUC DAS). Later on the 4th, another set of storms developed along the southern boundary of the previous night's activity (Figure 38, NWS). Although the storms were largely oriented in a SW to NE line across northern Illinois (Figure 39, NWS), most of the individual cells were traveling parallel to the line as it moved very slowly southeastward, causing tremendous rain totals to accumulate (Figure 40, NWS). A cooperative observer in Morrison, in northwestern Illinois, reported measuring 7.85 inches of rain in a period of approximately 15.5 hours. This precipitation total exceeded the amount of rain expected to fall in 24 hours once in a hundred years at that location; due to the briefer duration of this event, the odds of this happening in any given year are larger that 1 in 100. The nearby town of Sterling, IL, received 8.58 in of rain. Cities such as Rockford, IL (6.16 in), and Dubuque, IA (6.61 in), also received tremendous rains; in Rockford, a teenager who slipped into a drainage ditch is lost and presumed drowned. Chicago received less rain (2.73 in), but storms caused transportation difficulties, including the cancellation of several hundred flights due to winds and repeated lightning strikes and delays of other flights by two hours or more. One of the lightning strikes hit the tarmac, which created a one foot wide hole. Nearby, a baseball coach was struck by lightning and died 2 days later from his injuries. Storms also knocked out power for thousands of customers in towns and cities throughout the three-state area affected by the storms.

Flash flooding and river flooding occurred during and following the rain. In northeastern Iowa, southern-most Wisconsin, and northern Illinois many small rivers overflowed their banks. In northern Illinois, the Green River near Geneseo, IL, exceeded flood stage by 6 feet early on June 5 (Figure 41, USGS). The Rock River, draining a much larger area, took until the 7th to reach a record flood crest (for the time of year) near Joslin, IL, of over 19 feet, 7 feet above flood stage (Figure 42, USGS). One levee gave way in a rural section along the Rock, resulting in the flooding of farm fields in that district. Several boat rescues were also required by the rapid rise of the river flooding a campground. In southwestern Wisconsin, 25 homes were evacuated due to creek flooding. A trailer park was flooded on the north side of Dubuque, IA, and other communities along the Maquoketa River were also partially flooded, especially its name-sake town of Maquoketa, where the river was 10 feet above flood stage on the 5th (Figure 43, USGS). Charlotte, IA, along Deep Creek, was also hit very hard by flood waters. The governor of Iowa declared state disaster status in seven counties. Another affect of the tremendous rains was to cause many communities to bypass sewage treatment plants and release raw sewage into rivers throughout the region. Ten communities in Iowa bypassed treatment plants, and a number of communities in Wisconsin along the shores of Lake Michigan did the same. Milwaukee released more than 21 million gallons of partially treated waste water.

Major Flooding in Northwestern Minnesota.
The National Weather Service radar summary of the June 9-11 precipitation event in northwestern Minnesota (Figure 44, NWS) illustrates the extreme precipitation totals in the region. The Minnesota State Climatology Office (MN SCO) gathered rainfall observations from many locations and data sources to show that the event was as bad as was indicated by radar (Figure 45, MN SCO). Their report also indicates individual measurements of rainfall of 12 inches in Roseau and 14.55 inches near Lake of the Woods. Of the rivers flooding, the most significant damage occurred when the Roseau River set new all-time crest record of 23.34 feet at Roseau, a town of 2,500 near the Canadian border. The river rose more than 15 feet in less than a day (Figure 46, U.S. Army Corp of Engineers - USACE), and temporary sandbag dikes did not hold; the levees around the Roseau River, good to a crest of about 22 feet, were breached and overtopped, flooding almost the entire town. About 95% of the homes and businesses in Roseau were flooded. A focused effort did save the Polaris manufacturing site, home to 1,800 jobs and a major economic force in the region. The Wild Rice River reached a crest of more than 10 feet above flood stage at Hendrum (Figure 47, USGS), but the largest town along the river, Ada, had sufficient levees to keep the water out. Rebuilt after the 1997 great flood and topped off with an extra foot of packed clay, the dike system around Ada survived intact, although Ada itself became an island and was cutoff by surrounding flood waters. Finally, the Red River of the North was still rising days later, and likely to flood after the 11th. Many rural locations along rivers in northwestern Minnesota were also flooded, driving out farm families and other residents living outside the protection of levee systems.

National Guard troops were dispatched to the most severely affected counties in northern Minnesota, and 13 counties were declared federal disaster areas on June 14. The regional USDA director reports that nearly 2 million acres of planted crops in the Red River Valley in Minnesota have had crops destroyed by flood waters or damaged to the extent that crop insurance claims will be filed. Most of these areas will not be replanted this season, given the time it will take for fields to dry and the short growing season. Near Roseau, more than 500 farm and home buildings were damaged. Transportation was disrupted in many places; roads and bridges were damaged as well as flooded, and other forms of infrastructure were damaged also. By the end of the next week, the river water had left Roseau, where 95 percent of homes were damaged by the river. The most recent estimate of the cost of damage due to the flooding rains in the region is more than $370 M, making it a quite noteworthy event in regional climate history. Roseau County was given full disaster status first, while 12 other counties were given Federal disaster status about a week later (Figure 48, Federal Emergency Management Agency - FEMA).

Even though far northwestern Minnesota was not hit with rain as hard as some other areas of Minnesota during June 18-20, the 4-7 inches of rain that did fall caused many rivers in the area to return to and in some cases exceed the high stage of the flooding earlier in June (Figure 49, USGS). This was especially true along the Wild Rice River, which exceeded its record crest set earlier in June at Ada by a foot. Dikes held at the larger communities of Ada and Twin Valley, which also set a new record crest (Figure 50, USGS). However, some 19 homes were flooded and extensively damaged in and around Mahnoman, and dozens of others received some water damage in many small towns and farmsteads along the rivers. This toll, while significant, is fairly small compared to the 2,706 home damaged and 52 homes and buildings destroyed by the June 9-11 rains. Fortunately, some areas of central and northeastern Minnesota were experiencing abnormally dry conditions previously and were able to absorb much of the rain that fell in these areas without major flooding. Flash flooding did cause road damage and home flooding that was still being evaluated late in June. The reduced rate of rain in the last 5 days of June helped in the areas flooded by previous rains in northern Minnesota. The Wild Rice River at Hendrum, MN, finally had its second crest and started downward (Figure 51, USGS), as the water drained into the Red River of the North and headed to Canada.