By GILLIAN POMPLUN | Crawford County Independent
Compounding weeks of repeated, punishing waves of severe weather, flash flooding, flooding, tornadoes and high winds, and heat waves, an EF1 tornado, with peak winds of 105 miles per-hour, touched down near Norwalk on Aug. 11. The tornado was on the ground for about six miles.
According to the Monroe County Sheriff’s Office, power lines were blown down in the storm, but power was quickly restored. In addition, part of the Elroy-Sparta Bike Trail was impassable due to trees covering the trail. There were no injuries associated with the storm.
What looked like a tornado also was spotted in the same time frame just south of Viroqua. That storm caused the Viroqua Fire Chief to set off the outdoor warning sirens, but the tornado never touched down.
The tornado in Monroe County destroyed the Norwalk Sportsmen’s Clubhouse, as well as a barn owned by Joe Hansen in rural Norwalk. Not only were the club’s possessions destroyed, but so was the flood warning system for the PL-566 flood control dam, the Tri-Creek wet dam, in Norwalk.
That structure is the only PL-566 flood control dam on a Kickapoo River tributary (the unnamed tributary leads to Morris Creek, which leads to the Kickapoo north of Ontario). It is a wet dam because there is a permanent impoundment or lake behind the structure. When that impoundment is full, it holds 781.989,120 gallons of water, and is classified by the Wisconsin Department of Natural Resources as a high-hazard dam.
According to Monroe County Conservationist Bob Micheel, the flood warning equipment dated from 1992. Micheel said that after the tornado, the master relay system for the flood warning system is still upright, but the surrounding structure is destroyed. He said that power and the phone landline was knocked out, which complicated their attempts to evaluate the system.
“I’m talking with the company about upgrading our system into today’s technology,” Micheel explained. “An equipment upgrade plan and associated cost will be coming soon.”
Rainfall monitoring
Released late last week by Monroe County Land Use Planner Roxie Anderson, data from the Monroe County Climate Change Task Force about rain events between Aug. 7–9 help to explain in part how the recent Kickapoo River flood came to be. Despite large volumes of water falling in the Kickapoo River headwaters in Monroe County, however, the total floodwater moving through the system came from all points up and down the valley where rainfall volumes exceeded soil capacity to infiltrate water, or where they exceeded the capacity of existing vegetation on the landscape to slow it down.
The results from Monroe County’s rain gauges are astonishingly detailed and provide emergency managers and concerned citizens with detailed data that can help them to understand what is happening on the landscape. Monroe County is in the final stages of working with the National Weather Service in La Crosse to have the data served in almost real time on the NWS Southwest Hydrology Monitor web page.
Unfortunately, no such detailed rainfall data is currently available for the rest of the Kickapoo River Watershed, from Ontario to Wauzeka. U.S. Geological survey does have gauges on the river at Ontario, La Farge, Readstown and Steuben, but this data is not made available to the public in the same way, or as quickly, as the Monroe County data soon will be.
In the report summary, it reads: There were six rain events recorded on Saturday, Aug. 7, through early Aug. 9. Station 571 on Market Road (in the Little La Crosse River Watershed) went offline after the third rain event. Jared Tessman, Monroe County Emergency Management Coordinator, reported that there was a significant amount of debris that accumulated by the station.
Roxie Anderson reported that investigation of the station revealed that it was missing an antenna. She said that this could be as a result of weather or possibly of vandalism.
Klinkner gauge
A weather monitoring station with a device that measures rainfall amounts and intensities is placed on the Gerry Klinkner farm on St. Mary’s Ridge in Monroe County. Water from this location runs off into two watersheds — the Kickapoo River and the Little La Crosse River watersheds. In the report, it is described as ‘Station 573.’
In the first series of rain events, on Aug. 7, total rainfall between 8:36–10:35 a.m. was 1.38 inches. In the second rain event that day, between 11:46 a.m. and 1:46 p.m., 2.29 inches were recorded. In the third rain event that day, between 3:06–4:36 p.m., 3.76 inches were recorded. That means that a total of 7.43 inches of rain fell at that location between 8:36 a.m. and 4:36 p.m.
In the second series of rain events, on Aug. 8, the total rainfall between 4:16–6:56 a.m. was 0.89 inches. In the second rain event that day, between 1:06-2:36 p.m., 1.08 inches of rain was recorded. In a rain event on Aug. 9, between 1:56–5:16 a.m., 1.87 inches of rain was recorded. That means that on Aug. 8, and into the early morning of Aug. 9, a total of 3.84 inches of rain was recorded at that location.
In total, at the Klinkner Farm location, from 8:36 a.m. on August 7 until 5:16 a.m. on August 9, a total of 11.27 inches of rain was recorded by the gauge.
Little La Crosse gauges
The two gauges in the Little La Crosse River Watershed are located on Market Road and Nebraska Avenue and are known as Station 571 and Station 572. Both are located on streambanks in the headwater area of the Little La Crosse River, just down the ridge from Cashton.
In the first series of rain events at the Market Road station, on Aug. 7, total rainfall between 8:36–10:35 a.m. was 0.56 inches. In the second rain event that day, between 11:46 a.m. and 1:46 p.m., 1.46 inches were recorded. In the third rain event that day, between 3:06-4:36 p.m., 1.62 inches were recorded. That means that a total of 3.64 inches of rain fell at that location on Saturday, Aug. 7, between 8:36 a.m. and 4:36 p.m.
Due to loss of its antenna, this station was offline for the rain events on Aug. 8–9.
In the first series of rain events at the Nebraska Avenue station, on Aug. 7, total rainfall between 8:36-10:35 a.m. was 0.32 inches. In the second rain event that day, between 11:46 a.m. and 1:46 p.m., 1.78 inches were recorded. In the third rain event that day, between 3:06-4:36 p.m., 1.83 inches were recorded. That means that a total of 3.93 inches of rain fell at that location on Sat., Aug. 7, between 8:36 a.m. and 4:36 p.m.
In the second series of rain events, on Aug. 8, total rainfall between 4:16-6:56 a.m. was 0.89 inches. In the second rain event that day, between 1:06-2:36 p.m., 0.80 inches of rain was recorded. In a rain event on Aug. 9, between 1:56-5:16 a.m., 0.39 inches of rain was recorded. That means that on Aug. 8 and into the early morning of August 9, a total of 3.84 inches of rain was recorded at that location.
In total, at the Nebraska Avenue location, from 8:36 a.m. on Aug. 7 until 5:16 a.m. on Aug. 9, a total of 6.01 inches of rain was recorded by the gauge.