REGIONAL — A relatively light snowpack and lingering drought conditions across northeastern Minnesota are pointing toward a favorable outlook for spring flooding in the Rainy River Basin, although minor flooding remains possible in some eastern headwaters rivers.
That was the message delivered Monday during an informational session held by the International Rainy-Lake of the Woods Watershed Board’s Water Levels Committee, which is reviewing current conditions as it prepares to set the spring rule curve that governs water releases through the basin’s system of lakes and dams.
Ketzel Levens, a meteorologist with the National Weather Service office in Duluth, said current conditions suggest the basin is entering the spring melt season with relatively limited runoff potential.
Snowpack across much of northeastern Minnesota remains relatively modest. Measurements show snow water equivalent levels of roughly one to five inches across most of the region, with higher amounts primarily near Lake Superior.
“Snow water has huge grading across the basin, below normal in the west, near to slightly above normal in the east,” said Levens. “We see that reflected in some of our spring flood outlooks as well. And we’ve also seen the fact that we just don’t have a ton of SWE in our snowpacks.”
Dry conditions that developed last fall are also continuing to influence the basin’s hydrology. Much of northeastern Minnesota remains in some stage of drought heading into spring.
“We’ve had drought across the basin,” Levens said. “We had a really dry fall. Our streamflow and winter precipitation have largely been below normal, and we haven’t been able to seriously make up some of those deficits that built in the fall.”
River conditions entering spring are also favorable from a flood risk perspective. Most rivers remain ice covered and winter streamflows across the region are generally normal to below normal, meaning waterways have additional capacity to absorb snowmelt before reaching flood stage, Levens said.
Forecast models show the greatest potential for minor flooding in rivers draining the eastern headwaters of the basin. At the South Kawishiwi River near Ely, for example, the weather service estimates about a 25 percent chance of minor flooding later this spring, while the probability of moderate flooding remains below five percent.
“…all the other points (in the basin) that river forecasts and outlooks are produced for have a 5 percent chance or less, and that 25 percent chance is about normal for that forecast point,” Levens said.
Even if minor flooding occurs in headwaters areas, impacts would likely be limited.
“This is when we have some flood waters that are encroaching on some of the lowest Boundary Waters campsites,” Levens said. “Some portages might be a little wetter than normal, and you might have some campsites that have one less tent pad or it’s a little bit funkier to get a canoe onto it.”
While current conditions point toward a relatively manageable spring melt, officials cautioned that weather patterns in the coming weeks will ultimately determine how rivers respond.
“As conditions stand right now there might be a chance for below normal river flows and levels this spring, but there still remains uncertainty in the timing and amount of spring rainfall,” said Alexandra Lavictoire, senior water resources engineer with the Lake of the Woods Control Board Secretariat. “It’s really hard to say right now at the beginning of March.”
The watershed board uses the seasonal outlook to guide water management decisions across the Rainy River Basin, including lake levels on the Namakan chain and Rainy Lake and the operation of dams at Kettle Falls and International Falls.
“In any given year, we’re just as concerned about either a flood or a drought, high water or low water happening,” Lavictoire said. “Both are on our radar until we get further along and have a better idea of what that specific year will bring.”