Storms are fickle. One might drop several inches of rain or snow in Maple Grove, but barely a trace across the border in Brooklyn Park.

Hail could fall in Washington County but not in neighboring Ramsey or Dakota counties

The National Weather Service relies on reports and precipitation measurements from the public to get a better understanding on the impact storms have. It is putting out the call for observers to join the Community Collaborative Rain, Hail and Snow Network, or CoCoRaHS for short.

"The great thing about CoCoRaHS is you report what you can, when you can, and every report helps us as climate scientists do what we need to do," said Minnesota State Climatologist Luigi Romolo. "This is critical information with respect to drought monitoring and flood management."

The weather service has measuring stations at the Minneapolis-St. Paul International Airport, its offices in Chanhassen and on the University Minnesota's St. Paul campus. There also are automated stations in New Hope, Rosemount and Stillwater.

Volunteer observers can help fill in the gaps. The Weather Service gets about 100 to 150 reports a day, but there is always room for more, Romolo said.

"Not everyone reports every time, or they report for a while, and then for whatever reason, they stop," he said. "The more observers we have, the more likely we are to get more reporting."

Observers need a standard 4-inch diameter rain gauge and internet access to relay reports to the CoCoRaHS app or website. Those without a rain gauge can still send in snowfall amounts, snow depth, hail and other significant weather reports, Romolo said.

CoCoRaHS is a nationwide network of citizen observers. Each March, there is a competition among the 50 states to sign up new volunteers. Minnesota has been the champion for four years running. Last year the state enlisted 600 new volunteers. To sign up visit https://www.cocorahs.org/Application.aspx.