Ice jam results in near-record low river level

FILE: An ice formation occurred Tuesday, Feb. 17, 2021, on the Missouri River, about 5 miles upstream from the Missouri River Bridge in Jefferson City.
FILE: An ice formation occurred Tuesday, Feb. 17, 2021, on the Missouri River, about 5 miles upstream from the Missouri River Bridge in Jefferson City.

The National Weather Service in St. Louis continues to monitor an ice jam on the Missouri River near Jefferson City and what effects, if any, might occur as it breaks up with warmer temperatures coming into the area.

NWS hydrologist Mark Fuchs said the second-lowest level to ever be recorded at their gauge at the Missouri River Bridge took place Friday when the river reached -0.42 feet below zero gauge.

The record low level occurred in February 1908, when it hit -1.1 feet below zero gauge.

When a river gauge reads zero or in the negative numbers, it does not mean the river has gone totally dry or is running below ground, Fuchs noted. It means the gauge is reading at or below the agreed-upon zero level.

The formation occurred Tuesday about 5 miles upstream from the bridge. At that time, the river was running at about 4 feet, below the normal 9-foot level.

As temperatures rise, Fuchs said, the river level will go up. Although there are above-normal amounts of snow along the river, it shouldn't have much effect on the river's levels as it melts.

"There's also been drought in the Dakotas and in Nebraska along the river, and those areas didn't get any significant snows from this latest round of winter weather," Fuchs said.

Also keeping an eye on the ice are officials at Ameren Missouri. Spokesman Brad Brown said the utility company is watching the ice situation around Bagnell Dam at the Lake of the Ozarks, which has been a key power-generating source for Ameren during this past week of arctic cold.

"It's highly unusual for the Lake of the Ozarks to completely freeze over, and that shows just how extreme the weather has been in the past week," Brown said. "Lake discharges were higher earlier this week than they are now."

Last Sunday, Bagnell Dam had an average discharge between 35,000-36,000 cubic feet per second. By the end of the week, it was down to 12,000 cubic feet per second.

Brown said Ameren understands the concerns dock owners have been expressing about potential damage to docks due to the change of lake levels.

"We are balancing that with our need to supply energy to our customers and supporting the energy grid," Brown said. "We're also working with the Army Corps of Engineers and National Weather Service to support vital operations, including municipal water intakes, downstream on the Missouri River due to the ice near Jefferson City."

U.S. Coast Guard officials said Friday they were transmitting a broadcast notice to mariners alerting all river traffic users of the icing situation on the Missouri River.

"The ice appears to be an ice bridge and not an ice dam due to the prevailing evidence that water has continued to flow beneath it," Lt. Jim Long said. "The Coast Guard will continue to support the U.S. Army Corps of Engineers Kansas City District as the lead federal agency in determining the appropriate actions needed to ensure the river remains navigable."