During flood events in 2016 and 2018, Palo had to rely on water level forecasts from a gauge site in Vinton, more than 20 winding miles up the Cedar River to the north.
But starting Jan. 15, the city will have its own forecasting site, allowing emergency managers and residents to better predict river levels and prepare for rising water.
“One of the reasons we wanted that was because the last chance we have to see what is going to happen is in Vinton,” said Steve O’Konek, Linn County Emergency Management coordinator. “It really didn’t tell us much.”
The National Weather Service last week announced two new Cedar River forecasting sites, Palo in Linn County and Cedar Bluff in Cedar County. Both locations already have gauges measuring the water level and flow, but the Weather Service will start providing forecasts, as well as watches and warnings as necessary when the river is high.
“We use observational data from the rivers, rainfall and forecasts of rainfall 24 to 48 hours out to put in a model to determine what the forecast is going to be,” said Jessica Brooks, a service hydrologist in the Weather Service’s Quad Cities office. “We take that model data and put it out on the website.”
The agency decided to add forecasting based on requests from emergency managers and city officials, she said. The gauges in Palo and Cedar Bluff have been collecting data for at least four years, another criteria for being a forecast site, Brooks said.
The Weather Service will forecast from the Blairs Ferry Road bridge in Palo when the Cedar River reaches 11 feet. Minor flood stage there is 12.5 feet and major flood stage is 17 feet.
Forecasting will start at the County Highway F28 bridge in Cedar Bluff when the river is 12 feet. The minor flood stage there is 16 feet and major flood stage is 26 feet.
When heavy rain caused the Cedar River to rise in September 2016, Palo officials knew they couldn’t rely exclusively on flood forecasts from Vinton and Cedar Rapids, City Administrator Trisca Dix said.
“Our gauge reads a lot differently than Vinton,” she said.
Palo officials worked closely with the Weather Service to make sure they had the best data for their community and tried to spread the word.
“We were in a good state of preparation, we just had to go through added hoops,” Dix said.
Palo hired a consultant, took photos and collected data to prepare for next time, she said.
The Cedar crested in Palo at 17.7 feet in 2016, affecting 14 houses and causing an estimated $314,000 damage, according to an Oct. 20, 2016, Gazette report.
The distance a flood stage forecast remains accurate could range from 10 to 50 miles, depending on the speed of the river and topography, Brooks said. The new Palo forecast is expected to extend from the Benton County border to the northwest side of Cedar Rapids.
The Cedar Bluff forecasts cover the river in parts of Johnson, Cedar and Muscatine counties, Brooks said.
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