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Lake Superior sediment-heavy after torrential rains

The downpour took place last weekend in parts of the U.S. Upper Midwest – Wisconsin, Minnesota and especially northern Michigan. Satellite images show the effects on Lake Superior, the largest of the Great Lakes of North America.

Lake Superior discolored by sediments. Image acquired on June 19 by the MultiSpectral Instrument on the European Space Agency’s Sentinel-2 satellite, shown here via NASA Earth Observatory.

NASA Earth Observatory reported this week on the massive rain that fell last weekend in northern Michigan and parts of Wisconsin and Minnesota. The June 19, 2018, image above shows Lake Superior discolored by sediments. NASA Earth Observatory explained:

Torrential downpours hit parts of northern Michigan and Wisconsin last weekend, and swollen rivers sent sediment pouring into Lake Superior. Soil, sediment, and other particles ran off farmlands and towns, discoloring the water in the rivers and the lake.

This June 19 image … shows a portion of the Bois Brule River and the Brule River Boreal Forest in Wisconsin. New, darker sediment is flowing into an already discolored Lake Superior.

This pair of images shows the shoreline of Lake Superior before (June 14) and after (June 18) the downpour. Splotches of tan, red, and orange along the lakeshore indicate where rivers and streams carried muddy floodwater. The sediment is dominated by iron-rich soil called spodosols. These images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite, via NASA Earth Observatory.

Michigan appeared to be the hardest hit. NASA Earth Observatory reported:

In a matter of hours on June 17, 2018, torrential rains transformed parts of Michigan into a “state of disaster.” Early morning storms swept through the Upper Midwest, creating flash floods, a few fatalities, and historic property damage.

The potent storms developed when moisture in the mid and upper levels of the atmosphere from Hurricane Bud merged with a lower-level air mass rich in moisture …

Houghton County was hit the worst in Michigan. The town of Lake Linden received between four to seven inches of rain in seven hours. Nearby, the Trap Rock River received three inches, and its discharge was 331 percent above normal for June 17, 2018. The graph shows a connection between the amount of rainfall and river discharge, which is highlighted in the satellite image above. The graph shows how the increased rainfall over the area correlated with the high amount of river discharge for Trap Rock River. The data in this chart was provided by U.S. Geological Survey Water Resources.

Data acquired June 1-19, 2018. Image via NASA Earth Observatory.

Bottom line: Satellite images and info about the massive rainfall over the U.S. Upper Midwest (Michigan, Wisconsin, Minnesota).

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Deborah Byrd

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