Evapotranspo-what?

In order to make our forecasts understandable and memorable, Meteorologists use ordinary terms to describe our weather. However there's one thing going on this time of year that only sounds complicated. We're talking about evapotranspiration. That's the moisture (or water vapor) that healthy plants give back to the atmosphere. With the help of our friend Bill Steffen over at WOOD-TV in Grand Rapids, our own Justin Gehrts decided to crunch some numbers today.

Each stalk of corn gives 53 gallons of water to the atmosphere via evapotranspiration each year.

There are 20,000 stalks of corn (on average) in each acre of farmland.

That means that an acre of corn will give off 1,060,000 gallons of water each year. During the peak summer months, corn fields can put more water into the air than a lake!

Because of the massive flooding in Iowa earlier this year, 2 million acres of corn were lost. Adding up all of the lost evapotranspiration yields 2 trillion gallons of water. That's 2,000,000,000,000 gallons!

As Bill Steffan points out in his blog, that may be a reason why our computer models are overdoing dewpoints, rain chances, and rain amounts. However the fact that there's less evapotranspiration this summer may mean some pretty mean heat coming in the next few days and weeks.