MOUNTAIN HOME, Ark.-The next time the skies darken and raindrops begin to fall, the weather station at the Norfork Dam will be there to record the precipitation, just as it has done for the last three-quarters of a century.
National Weather Service officials on Thursday presented the U.S. Army Corps of Engineers with an award recognizing the 75 years of rainfall data collected by Corps employees at the dam, which dates back prior to the dam's construction in 1941.
The Baxter Bulletin reports that the weather station is part of the nationwide NWS Cooperative Weather Observer Program, where nearly 11,000 volunteers provide daily weather reports. In all, the NWS Little Rock office receives weather data from over 150 stations scattered across 45 central Arkansas counties.
"It's pretty remarkable that this has been here over 75 years now," said Sean Clarke, a meteorologist and observation program leader for the Little Rock office. "The consistency of the data is just amazing."
Accepting the award on behalf of the Corps of Engineers were Jon Hiser, the operations manager for the Corps of Engineers Mountain Home office; Steve Hernandez, the power plant superintendent for the Norfork and Bull Shoals dams; and Terry Madden, Corps of Engineers senior mechanic.
"Every maintenance crew as long as I can remember has been involved with the weather reporting," Hernandez said. "You're talking 75 years of collecting, imagine the generations of workers that has been involved with that."
Rainfall data recorded at Norfork Dam is compiled as part of the National Climatic Database and is published by the National Climactic Data Center for use by the public. The rainfall data is used to support climatology and river forecasting, as well as agricultural, construction and recreational interests in the Norfork Lake area.
"If we get a station reporting for 20 or 30 years, we're good," said Steve Drillette, chief meteorologist of the NWS Little Rock office. "Not only has it been 75 years, we looked through the records and it's very consistent, with very few missed days. That's necessary for accurate climate data.
In addition to longevity, the Norfork Dam rainfall station has stayed relatively still, being moved only a couple hundred feet over the course of its collections.
"When we start a site, we like to keep it going as long as we can," Drillette said. "It may change hands from family to family, but we try to keep it close to the same site as much as we can. Here, we have 75 years of data from pretty much the same location."
The Norfork Dam station records rainfall data, but other collection sites measure other weather-related metrics, like temperature, river levels or soil temperature.
"Without you, we wouldn't know how much rain is normal for the area," Clarke told the Corps officials. "It sets the baseline as to what is normal and the climate record for years and years to come."
The Norfork Dam rainfall station is located at the foot of the dam, outside the dam's power house. The rainfall equipment resembles a large, off-white milk can atop a concrete pedestal with a solar panel attached on its side.
The device records the amount of rainfall collected every 15 minutes. Measuring the rain in small increments can show the intensity of a rain shower as well as the sum total, Clarke said. Data is recorded to a flash drive, which is retrieved once a month by Corps employees and forwarded to the NWS.
Reporting was done daily until the mid-1980s, Hernandez said. Clarke added that NWS records indicate that measurements were taken hourly in the early 1940s.
Clarke said NWS officials originally believed that reporting from the dam site started in November of 1941, several months after construction of the dam started in spring of 1941.
"Usually, the rain gauge goes in first, before construction starts," he said. "Knowing that, we dug a little deeper in the records and found some extra data."
NWS records showed that reporting from the site actually began in February of 1941, before ground was broken on Norfork Dam.
"Within the first week, you guys were measuring snow for us," Clarke said.
Construction on the dam was completed in 1944, and the damming of the North Fork River created Norfork Lake.
The NWS enjoys a good partnership with the Corps of Engineers and often places sites at Corps projects, Clarke said.
"A lot of time, they request a site and I'm sure that's how this one started way back when," he said. "They wanted an idea of how much rainfall to expect when they started construction of the dam."
The rain gauge at Norfork Dam records the amount of rainfall collected every 15 minutes. That's 96 observations every day, and 35,040 reports in a year. Even if the station reported just once a day since it began in 1941, that is still almost 27,500 reports filed.