Lake Erie and Lake St. Clair are once again glowing neon green in NASA's latest satellite images, amid forecasts that this year's algal bloom would be one of the most severe in recent years.
Swirls of green can be seen spreading across Lake St. Clair and western Lake Erie in two photos, captured by the Landsat 8 satellite on July 28.
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Earlier in July, the U.S. National Oceanic and Atmospheric Administration predicted that the algae growth in Lake Erie could rival the record-setting 2011 bloom.
The latest bloom is expected to score between 8.1 and 9.5 on a 10-point severity index. The notorious 2011 bloom topped the chart at 10, making it the worst bloom ever observed.
This year's bloom will develop from west to east in the Lake Erie Western Basin starting in July, NOAA scientists predicted.
Algae in this basin flourish on nutrients, many from agricultural runoff, as well as sunlight and warm water temperature, NASA said.
Harmful algal blooms can lead to fish kills. They can also affect the safety of drinking water and make it more expensive for local governments to treat water.