Good news in the Western Lake Erie algal bloom forecast


The National Oceanic and Atmospheric Administration (NOAA) has forecasted milder algal blooms in Lake Erie for the second year in a row. In the past decade, western Lake Erie has seen a severe increase in the intensity of harmful algae blooms (HABs), usually seen from July to October, when the warmer weather gives way to ideal bloom conditions. This year’s bloom, however, is expected to be similar in size to the 2020 bloom, marking the first time in more than a dozen years where relatively mild blooms will have occurred in consecutive summers.


Early season predictions from around March to July are also based on measurements of phosphorus loading from the Maumee River which is the main source of nutrients for these blooms. The HABs on Lake Erie, as well as other bodies of water monitored by NOAA, are also tracked through a combination of satellite imagery which help measure bloom location and extent as well as water sample analysis and toxin sampling.


NOAA measures algal blooms on a severity scale from 1-10 based on the quantity of the bloom over a sustained period with blooms rated above a 5 considered severe. This year’s bloom is expected to be around a 3, with a potential range from 2-4.5, very similar to in 2020. Even so, NOAA has stated that the size of the bloom does not necessarily indicate its toxicity. HABs can be difficult to identify and the toxins present in cyanobacteria can concentrate at the surface and become highly dangerous for any living beings.


As of July 15, 2021, there was no detectable cyanobacteria by satellite in western Lake Erie.