CLEVELAND, Ohio — The official harmful algal bloom forecast for Lake Erie shows some improvement from last year, but is still worse than the levels in 2016. The National Oceanic and Atmospheric Administration with the Ohio Sea Grant and the Ohio State University predict a severity of 6 out of 10, while in 2017, the green plague in the western basin of the lake resulted from a severity of 8.’s sister website,, has the full forecast for the season with the suite of harmful algal bloom prediction maps.

Harmful algal blooms are rare in Cleveland, though the green slime shows up each July in the western basin of Lake Erie, ravaging the tourism industry. Blooms occur in shallow bodies of fresh water, when excess phosphorus and nitrogen mix with warm temperatures and sunlight.

Why you should care about harmful algal blooms in Lake Erie

The blooms off Cleveland, and in the rest of the central basin, are a different type cyanobacteria that blooms in the western basin.

In late June, bacteria raised warnings at Cleveland Metroparks’ Huntington, Edgewater and Villa Angela beaches, as well as at Veterans Memorial and Lakeview beaches in Lorain County.

Check the water quality at Ohio’s Lake Erie beaches here.