Michigan Harmful Algal Blooms (HAB) — NOAA Great Lakes Outlook

Algal blooms tracks NOAA Great Lakes Harmful Algal Bloom Outlook for Lake Erie, Saginaw Bay, and other Michigan waters. Bloom severity, location, and drinking-water risk. The reading is aggregated by Michigan Gateway from NOAA Great Lakes Environmental Research Lab (GLERL), an authoritative public source, and refreshed automatically throughout the day.

For Michigan residents this indicator is one of several environmental-hazard signals that inform day-to-day decisions — from whether it's safe to be outdoors to whether a specific community needs additional attention. Combined with the other environment indicators listed at the bottom of this page, it helps residents, journalists, and county officials build a fuller picture of current conditions in Michigan.

The current reading for this indicator updates live on the Michigan Gateway dashboard. The data feed below is fetched from NOAA Great Lakes Environmental Research Lab (GLERL) via the public /api/algal-blooms endpoint.

Harmful algal blooms (HABs) are excessive growths of cyanobacteria (sometimes called blue-green algae) that can produce toxins like microcystin. In Michigan they're most common in western Lake Erie and Saginaw Bay during late summer. The 2014 Toledo water crisis — when microcystin contaminated drinking water for 500,000 people — was caused by a Lake Erie HAB.

• Do not swim, drink, or let pets enter water that looks like spilled paint, has green scum, or smells musty.
• If exposed, rinse skin and eyes with clean water immediately. Watch for nausea, vomiting, or skin rash.
• If your drinking water comes from Lake Erie or Saginaw Bay, follow your water utility's daily advisories.
• Report a suspected bloom to EGLE at AlgaeBloom@Michigan.gov with photos and location.