Carlson says important data is encouraging, but there’s more winter to come, and the spring melt pattern is key
Longtime engineer Blake Carlson, whose particular areas of expertise involve agricultural drainage and flood control, says there’s no denying there’s a whole lot of snow out there. But when it comes to being concerned about a severe spring flood, Carlson, of Widseth Smith Nolting & Associates, says that there are factors that should ease some of the worry.
For one, the amount of moisture in the ground last fall at freeze-up is about average, and that’s the case for the most part throughout the Red River basin, he explained. “It’s certainly not excessive, so that’s a plus,” Carlson noted. “That means there is room for some water to go down and soak in when things start to melt.” On the flip side, he continued, soils that are “super-saturated” when things freeze in the fall can be a major red flag when it’s time for the spring thaw.
Then there’s the snow itself. While the snowpack is obviously pretty deep, Carlson says the water equivalency in the snow is below average. It’s a dry snow. “Typically, if you melt 10 inches of snow you’ll end up with an inch of water,” he explained. “Right now, it’s looking like less than that.”
Engineers will start taking actual water-content measurements later this month and into March.
“The current water equivalency is another positive contributing factor that lessens the chance of flooding in the whole basin,” Carlson said. “But, clearly, the biggest thing we have going for us particularly in Crookston is we have protection. We didn’t have these dikes in 1997.”
For generations, the spring thaw in Crookston was a stressful, sometimes gut-wrenching time, as the community was protected by “temporary” dikes that had been in place for decades and protected the town’s low-lying areas from a Red Lake River crest of 26 to 27 feet. In several springs, volunteers would be called out to sandbag at crunch time in particularly vulnerable areas.
But the winter of 1996-97 was especially severe, and it led to the Red River flooding East Grand Forks and Grand Forks. In Crookston, an early flood forecast of a record crest of the winding river through town led to a massive sandbagging effort several weeks in advance of the spring thaw involving hundreds and hundreds of volunteers and a sandbagging machine that was moved from one area of town to another as needed.
The river reached a record crest of 28.3 feet, and the moment of truth came when a huge ice jam backed up the water, and reports came into the City’s main Emergency Operations Center at the police department that water was starting to trickle over the tops of the sandbags on Pleasant Avenue in Sampson’s Addition. Meanwhile, Harold Slager, operating his backhoe fitted with a long steel I-beam, pounded and pounded on the ice jam, trying to break it up. Just as it appeared at least one low-lying neighborhood would succumb to a flood, Slager was able to bust up the ice, the jam gave way, and in mere moments the Red Lake River level dropped by several inches.
The City was subsequently able to secure a flood control project protecting the Woods Addition with certified levees. But it seemed like the community was years away from securing funding through the U.S. Army Corps of Engineers for similar projects that would protect Sampson’s Addition, Jerome’s Addition, Chase-Loring Addition and other vulnerable areas of town.
As efforts to secure funding for continued flood control efforts here continued, officials with the Minnesota Department of Natural Resources hopped on a boat and took a ride on the Red Lake River throughout Crookston to see how the old dikes looked from their “wet” side. What they saw alarmed them, and they went back to St. Paul and declared Crookston to be the most at-risk for flooding city in the entire state. At that point, the DNR and the Minnesota Legislature, through the DNR’s Flood Hazard Mitigation Grant Program, took the lead on funding flood control efforts in Crookston, and projects began to commence, one after another. The results are evident across the community today, with a certified levee system and other flood control measures in place that protect up to a river crest of approximately 30 feet.
Another major benefit of the flood control efforts can be seen in Crookston’s northeast corner, in the form of Crookston Sports Center. As part of the Jerome’s Addition project, the Civic and Sports arenas along East Robert Street had to be demolished to make way for a new levee. So the legislature, in a bonding bill, included $10 million to go toward the construction of a new arena in Crookston, and the $15.5 million CSC was the result, opening in January 2010.
Still reasons to be wary this spring
With more snow falling earlier this week and a few more inches possible this weekend, Carlson said flood control experts “definitely need to put out the caveat that there’s more winter to come.”
“You can never say there’s no chance (of a flood), because March can have a lot of snow, and the thaw can be so fickle,” he said. “It all depends on how it melts.”
A gradual melt that has temperatures above freezing during the day but then has things freeze up again overnight might try the patience of people dying for spring to finally arrive, but Carlson said that’s the ideal snow-melt pattern.
“I think it was 2008 or around there, nobody thought there was any risk of a flood, but just because of the way it melted, we got much higher levels on rivers than anyone forecasted,” he said. “It obviously depends on how much more snow we get, but the melt is crucial.”
“A melt in late March is usually not a problem; it melts during the day and freezes at night. That’s what you prefer,” Carlson continued. “If it doesn’t happen until the end of April, hold onto your seats. It can warm up in a flash and stay warm overnight, and then things can get real interesting.”