4 tornadoes confirmed in Memorial Day storm system as spring rain totals mount

After the Memorial Day weekend storms, the Big Sioux River has flooded the McKinley Park in Watertown.

It's the spring of severe weather and heavy rains.

Weekend storms, especially on Monday, resulted in minor flooding across the region. And four tornadoes were confirmed on Memorial Day, according to the National Weather Service.

There was damage, but no injuries, according to storm reports.

Amy Parkin, lead forecaster with the NWS office in Aberdeen, said the storms were the strongest when they reached Minnesota, although there were a few reports of minor flooding and tree damage in the Watertown area.

Strongest tornado had 140 mph winds

A tornado in Deuel County was the strongest, receiving a rating on the Fujita scale of EF-3. The highest wind gust in that tornado was 140 mph, according to a NWS storm survey report.

Three transmission towers were damaged, according to the report, and one farmstead also lost several outbuildings and had roof and window damage.

An EF-1 tornado was reported 4 miles northwest Clear Lake in Deuel County with peak winds of 115 mph. That tornado resulted in a damaged barn and a mangled grove of trees, according to storm reports.

More:As much as 7 inches of rain leave some Brown County, township roads underwater

A third tornado was reported 2 miles northwest of Clear Lake in Deuel County. It's rating was EF-1, with peak winds of 100 mph. A farmstead sustained damage, including a destroyed barn and machine shed, as well as windows blown out of the house. Several trees were also uprooted, according to the storm survey report. 

A fourth tornado 4 miles southwest of Labolt in Grant County was an EF-1 with peak winds of 97 mph. One farm had a roof ripped off of a barn. Roof panels were also blown off the house, and there were broken windows, a dented grain bin and uprooted trees. A second house sustained damage to half of its roof, with that portion being blown about half a mile, according to the storm survey report. 

More moisture across region

Watertown got 2.16 inches rain between Saturday and Monday, Parkin said. But that doesn't seem like much compared to the 7.3 inches reported during the weekend about 7 miles northeast of Aberdeen.

Aberdeen had 3.45 inches of rain on Monday alone and 4.09 inches during the holiday weekend.

Due to heavy rainfall during the holiday weekend, several camping sites are underwater at the Stokes-Thomas Lake City Park along Lake Kampeska in Watertown.

Despite the rainfall received in Watertown and the surrounding areas, there is currently little fear of serious flooding for Codington County, according to Emergency Director Andrew Delgado.

“We’re experiencing some minor flooding right now, but it will be dryer the rest of the week,” said Delgado Tuesday. “The Big Sioux Watershed will see the biggest flooding impacts, but the water levels should level out soon.”

The low-lying areas of Stokes-Thomas Lake City Park along Lake Kampeska, including some camping spots, were underwater Tuesday. And Brown County and township roads were dealing with floodwaters Tuesday, too.

A flood warning has been issued by the NWS for the Broadway Avenue area in Watertown, with the river in minor flood stage.

Storm systems moved fast, resulting in heavy rainfall in a short period of time, and that often results in flooding, Parkin said.

The Bath area just east of Aberdeen received about 6 inches of rain, Parkin said. And there were reports of 1-inch hail near Lake Norden in Hamlin County.

Aside from the tornadoes, the highest wind gust of 70 mph was reported just southwest of Big Stone City at 3:37 p.m. on Monday. A 66-mph gust was reported in Deuel County at 2:56 p.m. Monday.

The James River at Columbia in Brown County, which has been flooded for several weeks, rose about 5 inches during the weekend, said Parkin, pushing it to 18.46 feet. Even before last weekend, river was major flood stage.

For farmers in that area, that means more water on their land during a wet spring that has already made planting crops difficult in much of northeastern South Dakota.

Rain just keeps coming

There has certainly been more rain than normal this spring, Parkin said. There have been 10.82 inches of rain so far in Aberdeen, up from 4.2 inches a year ago and 3.6 inches in 2020.

Watertown has seen a similar pattern, having received 8.41 inches of rain in April and May compared to 4.28 inches a year ago and 3.92 inches in 2020.

Precipitation totals for the year are up across the region. Year-to-date totals followed by normal totals though the end of May for various communities follow.

  • Aberdeen: 12.53 inches of precipitation so far this year compared 7.35 inches normally through May 31.
  • Watertown: 9.78 inches compared to 7.27 inches normally.
  • Sisseton: 10.99 inches compared to 8.53 inches normally.
  • Mobridge: 6.39 inches compared 6.36 inches normally.
  • Britton: 12.56 inches compared to 7.28 inches normally.
  • Castlewood: 8.58 inches compared to  7.63 inches normally.
  • Ipswich: 10.4 inches compared to 6.63 inches normally.
  • Selby: 6.84 inches compared to 6.29 inches normally.
  • Webster: 12.42 inches compared to 8.43 inches normally.
  • Roy Lake: 10.36 inches comparted to 7.49 inches normally.
  • Hayti: 8.29 inches compared to 7.54 inches normally.
  • Faulkton: 10.77 inches compared to 7.86 inches normally.
  • Milbank: 10.37 inches comparted to 8 inches normally.
  • Wilmot: 9.47 inches compared to 8.25 normally.
  • Donald: 7.87 inches compared to 6.78 normally.

A mixed forecast

The NWS forecast calls for some dry, sunny weather in the Aberdeen area before a 40% chance of rain Friday night and more rain possible through the weekend.

For Watertown, the scenario looks the same. Some sun and mild weather are projected until Friday night. Then, the NWS calls for a 60% chance of rain with more possible Saturday.