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Citizen scientists help record rainfall data

Sharon Sullivan
ssullivan@gjfreepress.com
Rain gauges like the one shown are used to record daily precipitation around the country.
Community Collaborative Rain, Hail and Snow Network. |

Torrential rains in some parts of the Grand Valley Tuesday night brought 1.5 inches of rainfall — “a significant amount” for an area that averages just 9.42 inches a year, said Joe Ramey, a meteorologist with the National Weather Service in Grand Junction.

The Weather Service at Grand Junction Regional Airport reported .21 inches compared to other parts of the valley where numbers were much higher.

So far, July is wetter than normal with .55 inches for the month — the average is .27. Last year, July received .77 inches of rainfall.



“So we’re above average so far, but we’re behind for the year,” Ramey said. “We should have 4.56 inches; we have 3.97 so far for the year. But it’s catching up nicely.”

Volunteers nationwide and in Grand Junction help track precipitation through a nonprofit organization based at Colorado State University in Fort Collins.



Community Collaborative Rain, Snow and Hail Network (CoCoRaHS) was founded in 1998 in response to the 1997 Ft. Collins flood.

People who sign up for the program measure rainfall in their backyards and then record the data online at http://www.cocorahs.org. CoCoRaHS operates in all 50 states, as well as parts of Canada.

“The original intent was to educate people on rainfall patterns,” CoCoRaHS national coordinator Henry Reges said. “The data became so good the Weather Service and other entities began using it.

“It’s the largest daily source of precipitation measurement in the United States,” Reges said. “Rainfall is very variable; There can be buckets of rain, and two miles away be dry as a bone; The more observations the better.”

People who sign up for the program (at http://www.cocorahs.org) purchase a $30 rain gauge, receive a station name and number, and once a day between 7-9 a.m., measure the last 24 hours of rainfall. Even during dry spells, a report of zero is an important observation, Reges said.

CoCoRaHS has 19,000 such weather observers across the county, including 20 in Mesa County.

“We could double or triple” the number of volunteers in the Mesa County area, Reges said.

Lorna Naegele, who lives on Orchard Mesa, recorded in her backyard 1.02 inches of rainfall after Tuesday night’s storm.

“I think it’s interesting,” Naegele said. “I like knowing that I am participating in a nationwide study, and providing good data for people to do research.

“I like weather. I grew up on the shore of Lake Erie and I watched a lot of storms as a kid.”

There’s also a comment section on the website where volunteers can record their visual observations of stormy weather.

It’s a great way for citizens to be involved in actual science; their data is used, Reges said.

The recent thunder, lightening and rain are part of the monsoon season caused by moisture stemming from tropical Mexico.

The system weakens as it travels north, which explains the increased rains found in southern Colorado and northern Arizona during the summertime.

Forecasters at the weather service station in GJ were busy Wednesday watching storms, and keeping abreast of additional rainfall and potential flooding issues.

The current yearly rainfall average of 9.42 inches comes from averaging 30 extreme events together over a 30-year span, Ramey noted. The average is updated every 10 years.

“There could be anywhere from 13 inches to 5.5 in any given year,” he said. “Our weather, day to day, month to month, year to year, is quite variable.”


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