Foam on a river

Everyone is familiar with foam on an ocean beach when wave action is churning the water.  But foam on inland waters is less common, and large amounts of it raise questions about a possible industrial spill or other contamination of the river/lake.

There is another explanation, offered this past week by the meteorologist at our local news channel KWOW (photo credit Jonathan Hefty):

Heavy rain and warmer temps over the past few days are likely to blame for this foamy scene on the Pecatonica River in Blanchardville on Monday.

Because the ground is still frozen, much of Monday’s rain quickly turned into runoff and flowed towards area waterways. In the process, the ground water picked up dead plants, which have been decaying at a quicker rate due to this past weekend’s warm weather. As the plant matter breaks down, it releases fatty acids which, when mixed with water and air causing foam to form.

A quick search revealed a similar reassurance to the public for river foaming in South Bend, Indiana.

You learn something every day.