WISCONSIN DELLS (WKOW) – An expansive area of yellowish foam was seen floating down the Wisconsin River on Monday.

Jeff Neumann took this photo and sent it to 27 News.

WHAT’S HAPPENING

When leaves, twigs and other natural things fall in the water and begin decaying, they release bubbles, which then compile into foam.

You may see similarly foamy scenes on other waterways in southern Wisconsin thanks to our breezy and warm set up over the last week.

Heat speeds up plant decay which allows more foam to form, and the wind mixes the air with the water to create even more bubbles.

We likely see so much of it here because of human pollution from too much phosphorous in the water.

Excess phosphorous comes from industrial or wastewater treatment plants or storm water and septic tank run off from urban, farm, and residential areas.

Increased phosphorous in the water not only grows foamy scenes like this, but also feeds algae blooms in the summer.