Extended rain in forecast creates flooding concerns
Snow is taking a break this week and staying out of the headlines, presenting residents in the Brainerd lakes area and beyond with another Mother Nature potential weather fiasco—flooding.
A large, warm and wet system will pass through the Northland over the next several days.
The National Weather Service in Duluth issued a flood watch for Crow Wing, Aitkin and Cass counties among other counties in portions of central Minnesota and Wisconsin, which will go into effect 1 p.m. Wednesday, March 13, and run through 7 p.m. Thursday.
The NWS reported an extended period of rainfall will begin Wednesday afternoon and last through Thursday night, resulting in 1 inch to 1.5 inches of total rainfall. The rainfall combined with temperatures in the 40s will melt snow with little to no storage capacity due to the frozen ground, thus increasing the threat of flooding. The biggest concern will be street flooding, particularly in areas of poor drainage. Basement flooding also will be possible, along with roof leaks due to ice dams.
The added weight of the rain-soaked snow on roofs may cause them to collapse, especially on barns and outbuildings.
Weather service meteorologist Steve Gohde, the observation program leader, said this flood watch is different than the watches the NWS typically issues. This watch is not to alert residents about the rivers getting close to flood stage—which for the lakes area is observed on the Mississippi River in Aitkin and Fort Ripley. Rather, it's for people to be aware the rainfall will make it tough for urban street drainage. Gohde said the rainfall will not be able to percolate into the ground because of the frost.
"It's hard to say what will happen from home to home," Gohde said. "So people should make sure their sump pump is working well."
Gohde said the rain will add to the weight on the snow-covered roofs and if there are any ice dams, the weight will only exacerbate the troubles.
The good news is the snowpack will act like a white sponge and absorb the rain, up to a point. Gohde said the NWS suspects the rain will compact the snowpack, shrinking it. The rain should clean up the dirty snow on the roadway, but it will take a lot of sunny days to melt the snow.
Weather forecasters would like to see warmer temperatures during the day and freezing temperatures at night to melt the snow slowly, helping to mitigate the flooding concerns.
"Down the road there is a high probability of flooding on the Mississippi River," Gohde said. "We are looking at a 95 percent chance of minor flooding in Aitkin and Fort Ripley. There is an 83 percent chance of moderate flooding.
"In Brainerd, we don't have a flood stage set down by Kiwanis Park."
The flood stage in Aitkin is 13 feet and in Fort Ripley it is 10 feet. Moderate flooding is calculated at 18 feet.
Gohde said the March climate outlook reports show Brainerd may see a drier weather pattern in mid-March and above-normal temperatures at the end of the month.
The normal monthly high temperature for Brainerd is 38.9 degrees and the normal monthly low is 19.2. The outlook report shows the normal precipitation for March in Brainerd is 1.52 inches and normal snowfall is 8.4 inches.
The warmest March on record—when looking at the monthly average temperature for Brainerd—is 42 degrees in 2012; and the coldest is 11.5 degrees in 1899.
The highest observed temperature in March in Brainerd was 80 degrees on March 28, 1946; the lowest observed temperature is 35 below zero on March 11, 1948.
Brainerd's upcoming forecast
Wednesday, March 13: Showers after 2 p.m., with a high near 41. Chance of precipitation is 100 percent during the day and night. Showers are expected before 8 p.m. and rain after 8 p.m., with a low of about 34. An east wind of 5-10 mph, with gusts as high as 15.
Thursday: Rain, possibly mixed with snow before 3 p.m., then rain likely between 3-5 p.m., then snow likely, possibly mixed with rain after 5 p.m. High near 37. Breezy, with a north wind of 5-10 mph increasing to 15 to 20 mph in the afternoon. Winds could gust as high as 30 mph. Chance of precipitation is 80 percent. Rain and snow are likely before 10 p.m., then a slight chance of snow between 10 p.m. and 2 a.m. Friday. Chance of precipitation is 60 percent at night.
Friday-Sunday: No rain or snow is expected and temperatures will linger in the low 30s, reaching 36 by Sunday.