When it rains, they score: Volunteers tally precipitation | PostIndependent.com

When it rains, they score: Volunteers tally precipitation

by Dennis Webb
GSPI News Editor

When Fort Collins suffered a major flood on July 28, 1997, 14 inches of rain fell in some parts of town.

But other parts of town only got an inch or two.

For Nolan Doesken, assistant state climatologist at Colorado State University’s Colorado Climate Center, the incident demonstrated the need for better, more timely precipitation measurements in Colorado.

“People had no idea that a flood was coming because they hadn’t had anything like that rain only three to four miles away,” he said.

What was considered a 500-year flood resulted in five deaths, 54 injuries, some 200 homes lost and about 1,500 homes and business damaged.

More immediate, on-the-ground information could have been helpful in limiting death and damages from that catastrophe. Instead, it took Doesken months to get good information about precipitation patterns during the storm.

It doesn’t take that long now in Fort Collins, and soon it will take less time in western Colorado as well.

Calling all weather watchers

The Colorado Climate Center is currently recruiting volunteer weather monitors in Garfield, Eagle and Pitkin counties, after successfully setting up a monitoring network in Fort Collins.

About 80 people there enter precipitation information on a Web site.

Recently, about 25 people attended a meeting aimed at organizing volunteers in Grand Junction. A recruitment meeting is being held today in Glenwood Springs (see accompanying box).

Doesken said the Glenwood effort is being driven in part by the U.S. Bureau of Reclamation, which oversees reservoir operations, and the Colorado River Water Conservation District, based in Glenwood Springs.

Officials with these agencies hope that better precipitation reports will improve the ability to predict river flows right down to the hour in the Colorado River Basin, and to adjust releases from reservoirs accordingly.

This becomes increasingly important with a growing number of interests competing for water, and non-human water demands such as endangered fish habitat requirements also coming into play.

Malcolm Wilson, a water resource engineer with the Bureau of Reclamation in Loveland, said his agency is providing rain gauges for use in the Glenwood volunteer project.

“If we get a better handle on when, where and how much precipitation is occurring, that helps everybody in the basin,” he said.

On-the-ground accuracy

Doesken said Colorado’s “interesting” weather patterns and complex topography often lead to very localized storms.

Radar isn’t always a good indicator of what precipitation is reaching the ground, he said.

Doesken said information from volunteer monitors recently helped National Weather Service officials in deciding to put out flash flood warnings during a storm.

“They might have put them out anyway, but they had a whole lot more confidence seeing the observations than if they were just doing it off their radar,” Doesken said.

Usually, the information gathered by volunteers is incorporated into a once-daily update. But the system also allows for special up-to-the-minute updates during storms. The information can be viewed by anyone at http://www.cocorahs.org.

Ideally, he said, there would be one weather observer per square mile to monitor storms.

Traditional observing stations for the National Weather Service amount to one every 625 square miles. Locally, said Doesken, there are stations at KMTS in Glenwood Springs, at the Shoshone power plant in Glenwood Canyon, and in Aspen and Rifle.

Those traditional stations are vital for purposes such as determining whether counties qualify for drought or flood relief, and won’t be replaced, Doesken said.

Still, the information is only as reliable as the people gathering it, and sometimes it isn’t gathered consistently, said Doesken. More weather monitors will bring increased reliability, he said.

A job for weather junkies

While the monitors won’t be paid, Doesken says many people have other motivations for becoming involved.

“Water matters so much and … there are usually people that are interested in what they can learn by what’s falling from the sky,” he said. “There are a whole lot of folks that are just flat-out weather fanatics. They’re just kind of weather junkies.”

Water professionals also are apt to become monitors, and families and schools sometimes volunteer for educational reasons, said Doesken.

While daily reports are the most valuable for providing long-term precipitation patterns, participants don’t need to watch the weather every day, Doesken said. Any accurate data is helpful in the case of individual storms.

For consistency’s sake, participants use a standardized rain gauge that costs about $25 but is provided by the Colorado Climate Center or donors.

Participants also receive inexpensive hail measuring devices. Pieces of polystyrene covered with aluminum foil, they provide information on hail volume, size and characteristics based on the indentations made.

Doesken said he had hoped the Fort Collins program would last two or three years. Now it’s a half-decade old, and serving as the impetus for a much larger program.

“We’re realizing we’re just getting a good start,” he said.

Contact Dennis Webb: 945-8515, ext. 516


Two free training sessions on becoming a weather monitor will be held today at the Glenwood Springs Community Center, one from 4-6 p.m. and the other from 6:30-8:30 p.m. Information also is available at http://www.cocorahs.org.

Organizers also will be looking for a coordinator for the local monitoring program.

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