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posted: 3/3/2014 8:27 AM

Local volunteers help pros make sense of the weather

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  • This winter, DuPage volunteers are helping weather professionals track snowfall at more than 60 points across the county. A Lisle observer has counted 37 snowy days since Dec. 1.

      This winter, DuPage volunteers are helping weather professionals track snowfall at more than 60 points across the county. A Lisle observer has counted 37 snowy days since Dec. 1.
    Daily Herald File Photo

  • CoCoRaHS volunteers track daily rain and snowfall amounts in a standardized gauge, then enter their findings on a website for scientists to study.

      CoCoRaHS volunteers track daily rain and snowfall amounts in a standardized gauge, then enter their findings on a website for scientists to study.
    Daily Herald File Photo


In the musical "Camelot," the winter is forbidden until December and must exit on March the second. There also is a legal limit to the snow allowed to fall on the mythical hillside hamlet.

Within the lyrics, there is no restriction given to the number of single-digit and below-zero temperatures, but in my version I'd limit those to January.

It certainly is make-believe to order weather preferences; nevertheless, with the challenging winter we are having, daydreaming is allowed. The winter of 2013-14 is becoming one for the record books.

The National Weather Service reports that a little over half the days in the past seven weeks have recorded accumulating snowfalls. The meteorological winter, from Dec. 1 to Feb. 26, could finish in the top three coldest winters. The northern Chicago metro area has had a sustained snow cover since early December, and that is climbing into historical rankings.

Lisle resident Carl Grumbles reported 37 different days of snowfall since Dec. 1. His records show multiple days of 5-inch snowfalls; a snow he describes as light and fluffy rather than dense.

"I have seen some fascinating differences within even a few miles," Grumbles said. "I used to think everyone got the same rainfall, but now I know that is not true. I know farmers knew there was a rain difference from one field to another, but now I see it within my same suburb."

Grumbles is a longtime volunteer with CoCoRaHS. The Community Collaborative Rain, Hail and Snow Network has its acronym pronounced "coco–RAHZ." It is a nonprofit citizen-based source of reliable weather data.

The data from hundreds of CoCoRaHS volunteers across northern Illinois gives the local weather bureau valuable information. Each day volunteers record daily precipitation at their rain gauge and measure amounts of snowfall from their own backyard.

"It is not complicated to record," Grumbles said. "I have friends and neighbors ask me how much I have gotten or how much rain fell yesterday, because people are interested."

Naperville resident Edward Pacana has volunteered with CoCoRaHS since 2007 when a newspaper story caught his interest.

"I have always been interested in weather and an avid fan of weatherman Tom Skilling, whose forecasts go into great detail and explanation," said Pacana.

"In CoCoRaHS, I have an opportunity to contribute to the collection of weather data that benefits the public. It is good to know that my precipitation reports, along with all the other volunteers' reports, provide valuable information to the National Weather Service and other agencies."

Volunteers are filling in a part of the weather puzzle that never existed before. The data is used by the National Weather Service, meteorologists, hydrologists, farmers, emergency workers, mosquito control personnel and more.

"The CoCoRaHS observations provide valuable information for the river forecast and flood warning program of the National Weather Service too," said Bill Morris, National Weather Service hydrologist who looks at the volunteer reports daily from his base office in Romeoville.

"In addition to snow depth, hydrologists need to know snow-water equivalent -- this is the amount of water locked up within the existing snowpack that will be released as runoff into area streams when the melt begins."

Morris is the regional CoCoRaHS coordinator in Illinois and a volunteer observer as well.

CoCoRaHS began in 1998 in Colorado following a devastating flash flood that took both lives and property in Fort Collins. An extreme local downpour dumped 14 inches of rain between the existing recording stations.

The tragedy pointed out the need for pinpointed weather observations across a wider area to better serve the community.

Nolan Doesken, who maintained a historic weather station on the Colorado State University campus, set in place CoCoRaHS because he knew the importance of basic, local observations.

"Precipitation is much more variable than most other climate elements so there is clearly the need for more observation points to better understand the nature of precipitation," Nolan wrote in 2010.

Within the first 10 years of pinpointed observations, meteorologists found that one part of Fort Collins consistently gets about 25 percent more rain and snow than the other side of town. With long data records, weather predictions should be more targeted in the future.

Illinois was the 13th state to join the grass-root national effort. Today there are roughly 600 active observers, including about 65 observers in DuPage County, according to Steve Hilberg, Illinois CoCoRaHS coordinator.

More are needed, especially with the great variety of weather northern Illinois experiences. The more observers in a region, the more accurate the assessment of isolated thunderstorms, snowfalls and amounts of rainfall recorded.

CoCoRaHS has grown to become the largest provider of daily precipitation observations in all 50 states and in several Canadian provinces. Volunteers are needed across the country. It is easy to sign up and all ages are welcome.

Each March, CoCoRaHS has its March Madness, an effort to recruit additional observers.

Locally, CoCoRaHS volunteer training is planned for 10 a.m. to noon Saturday, March 29, at the University of Illinois Extension Will County Office, 100 Manhattan Road, Joliet. The program is free but preregistration is required. For details, call (815) 727-9296.

Popular new features in the CoCoRaHS training are short animations covering different aspects of observing. They are available at the CoCoRaHS YouTube channel,

A requirement to join CoCoRaHS is an interest in watching and reporting weather conditions. Observers need to purchase a $30 standardized CoCoRaHS rain gauge and have Internet access to enter reports. Details are at and click on Illinois.

A tough winter may give us something to talk about, but CoCoRaHS is giving us the tools to do something about it.

• Joan Broz writes about Lisle. Her columns appear regularly in Neighbor.

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