The possibility of ice jams occurring on the James River as releases from Jamestown and Pipestem dams continue into the winter is a unique aspect of this fall's flood, according to Jerry Bergquist, Stutsman County emergency manager and 911 coordinator.
"We've never done this before," he said, referring to monitoring the river for ice jams. "Anyone with any experience with ice jams on the James is dead."
The last ice jam in this area occurred 50 years ago and was the last major uncontrolled flood to strike the area, Bergquist said.
"There was an ice jam upstream on the Pipestem (Creek)," he said. "It gave way and dropped a lot of water into Jamestown all at once."
The April 16, 1969, edition of The Jamestown Sun carried the headline "Flooding no longer possibility -- It's Here." The story said the level of Pipestem Creek in Jamestown rose 4 feet overnight.
On the morning of April 16, 1969, the Pipestem was just over its flood stage of 12 feet. By noon the next day, the river was more than 5 feet higher.
"We didn't think it would be this quick," said Jamestown City Engineer Don Wenaas in the article. "But it's coming."
The water carried ice that caught on bridge structures in Jamestown, causing more ice jams resulting in more extensive flooding.
"Nearly one-fourth of Jamestown lay underwater today as a result of the Pipestem's watered fury," wrote Sun reporters Sam Lowe and Denys Fritch in the April 17, 1969, edition. "The flooding has created a state of emergency in the city and has produced a disaster area declaration from Gov. William L. Guy."
The Jamestown state of emergency included a ban by Mayor W.A. Taft on all travel in the city not associated with fighting the flood. The Jamestown Police Department was given the authority to arrest anyone suspected of "sightseeing" in the flooded areas.
The water was so high and flowing with such force in the Business Loop East area that a car that missed an approach to a parking lot began floating downstream. The vehicle occupant was rescued by local residents who created a raft out of inflated tractor tire inner tubes and boards.
In other parts of Jamestown, residents fought the flood with sandbags placed by the Jamestown unit of the National Guard, local college and high school students and the public. Still, the Anne Carlsen Center and Gardenette housing development were inundated with water and evacuated.
Officials in 1969 weren't sure of the crest of the Pipestem. The gauge on the river was completely covered with water the first day of the flood. Longtime residents in the community said the crest was higher than the floods of 1950 and 1966.
Jamestown Dam was built in the early 1950s and controlled flooding from the James River. The flood of 1969 was the impetus for the construction of Pipestem Dam in the early 1970s.
Since then, ice jams have not been a problem, Bergquist said.
Allen Schlag, hydrologist for the National Weather Service in Bismarck, said in a presentation Tuesday to local residents and officials that ice jams were fairly common on the Missouri River near Bismarck.
Schlag said ice jams this winter on the James River are a concern because the river current will be moving faster than other winters because of the high releases. That coupled with thinner ice that could break loose would cause accumulations of ice wherever an obstacle such as a bridge or downed tree stops the ice movement. If enough ice accumulates, it can cause the river elevation to increase behind the obstacle.
"On the James River, we're not sure how much increase in river level could occur from an ice jam," Schlag said.
Schlag said by reducing releases from the dams to a combined 800 cfs after the ice forms, the river level will be lower than it currently is, leaving some room for water behind an ice jam to rise while the river stays within its banks.
Still, he recommended residents along the river stay vigilant for changing river conditions.
Bergquist asked residents to call the Stutsman County Communications Center at 911 or 252-1000 if they see an ice buildup or obstacles that could cause ice problems. Law enforcement officers or Stutsman County Road Department staff would then check out the problem.
"This is all a learning experience for us because we've never dealt with these issues before," he said. "We have to learn without putting people in harm's way."