Examples of Harmful Algal Blooms (HABs)

A harmful algal bloom (HAB) can appear in various shades of green or blue and form scum, foam, or mats. Blooms can also resemble spilled paint, green globules, or grass clippings.

Some blooms may not be visible on the surface of the water at all times if they rise and fall in the water column during the day. Cyanobacteria may move or disperse depending on temperature, wind, and weather.

The photos in this gallery are representative of HABs in Utah, but bloom appearance can vary depending on the species of cyanobacteria and water conditions. When in doubt, stay out.

Pea Soup

Pea Soup HABs

Spilled Paint

Green Scum

Green Mats

Bright Green


Blue-Green Residue

Grass Clippings

Benthic Mats