LAKE ERIE, July 19, 2017 - Western Lake Erie will experience a significant harmful algal bloom this summer, potentially reaching levels last seen in 2013 and 2014, though smaller than the record bloom of 2015, according to a prediction by the National Oceanic and Atmospheric Administration and its research partners.

This year’s bloom is expected to measure 7.5 on the severity index, but could range between 6.5 and nine. An index above five indicates a potentially harmful bloom. The severity index is based on a bloom’s biomass – the amount of its harmful algae – over a sustained period. The largest blooms, 2011 and 2015, were 10 and 10.5, respectively. The blooms are blamed partly on nutrient runoff and soil erosion from fertilized farmland.