The Iowa Department of Agriculture, State Climatologist and National Weather Service are seeking volunteers to help measure the rain, snow and other precipitation that falls on the state. State Climatologist, Harry Hillaker, says the volunteers will help with what’s called the Community Collaborative Rain, Hail and Snow Network.
“This particular network, known as CoCoRaHS for short, is a national one that started back in 1998 by the state climatology office out in Colorado. And it was done in response to a major flash flood event they had had the year before that caused a lot of fatalities in the Fort Collins, Colorado area,” Hillaker says.
The idea is to get more reports to better track the wide variety of precipitation that can fall. Hillaker says Iowa has been part of the network for six years. “We’ve got about 300 or so registered Iowa members of that group and about 100 of those actually report fairly regularly across the state, and we’re certainly hoping to have way more than that,” Hillaker says.
The immediate goal is to have network members in all 99 counties. “I’d kind of like to see even more than that, where you have maybe one in every township across the state,” the climatologist says, “Because we do get such variability of precipitation across Iowa.”
Hillaker says Iowa has some long, narrow watersheds, and that means it’s important to know how much rain is falling across them. “If you look on a map — like the Des Moines River basin for one example — completely crosses the state of Iowa, but isn’t a very wide basin as far as what drains into,” Hillaker says. “It’s very often — in fact most of the time — any flooding that occurs along that river is probably a result of what goes on well upstream from where you are at.”
Hillaker says radar can now make estimates of rainfall, but he says having someone on the ground with a rain gauge is still the most accurate way to tell what’s going on. Volunteers would use a four-inch wide rain gauge. “It’s bigger than your usual hardware store variety gauge that you can pick up,” according to Hillaker “And they’ve done a lot of testing of that gauge and found it actually works extremely well as far as getting a good catch of actual rainfall. And compares very well with the official gauges that the National Weather Service uses, which are larger yet, and far, far more expensive.”
He says the plastic gauges used by the volunteers cost between 25 and 30 dollars. You can find out how to sign up to be an observer at the network’s website. “It’s got all the information about how to join the network, where to find the rain gauge, how to actually measure — especially snowfall and snow depth — which a lot of people aren’t familiar with how that is typically done. But, it’s got all kinds of information in there, everything you would need to know would be at www.cocorahs.org,” Hillaker says.
Volunteers from all 50 states and Canada now participate in the network. Hillaker says the more observers that can help in Iowa, the better picture they can get of the precipitation that falls on the state.