The rainfall, melting snow and frozen ground are not a good mix and are causing minor flooding in the Brainerd lakes area, including area school buildings.

Brainerd crews were out and about Thursday, March 14, clearing streets filled with a sloppy mix of rain, slush and snow and clearing out any storm drains they could to help with runoff.

The rain was light most of Wednesday and was expected to change to snow Thursday night, the National Weather Service in Duluth reported. The overnight snow accumulations were expected to be less than an inch in most spots, with the greatest snowfall in Koochiching County, where 2-4 inches was possible.

Daytime temperatures are expected to climb above freezing for most locations in the Northland Sunday through Wednesday, with overnight lows to remain below freezing. Brainerd could see temperature highs of 37 degrees Sunday, 38 Monday, 39 Tuesday, 43 Wednesday and 44 Thursday, March 21.

The mix of warmer temperatures during the day and below-freezing temperatures at night is what people should like to see, the NWS said, as this mix will slowly melt the snowpack and lessen the possibility of flooding.

Crow Wing, Aitkin and Cass counties are no longer in a flood watch, but the NWS reported flooding is still possible due to the frozen ground and deep snowpack, which may lead to poor drainage and blocked storm drains. Weather observers are concerned about the rain being absorbed by the snow, adding weight to an already heavy snowpack. This added weight could lead to roofs and decks collapsing. In addition, water could be an issue in buildings due to poor drainage.

Poor drainage was seen in the Brainerd area starting Wednesday night, as water in buildings was reported. Below, see how area agencies fared with the weather conditions.

What Brainerd Public Schools is seeing

Brainerd Public Schools is on spring break this week and school is not in session-so it should be a quiet week throughout the school buildings.

However, that wasn't necessarily the case Thursday as minor flooding caused some headaches for the school district. District officials announced late Wednesday it had to move its KinderClub and Fun 'N' Friends programs out of the Washington Educational Services Building to Riverside Elementary School for Thursday-Friday, due to water.

Earl Wolleat, Brainerd Public Schools building and grounds director, said the district has water in the cafeteria at the Washington building off Oak Street, water in the office at Brainerd High School off Fifth Street and in the maintenance area at Forestview Middle School in Baxter.

Wolleat said they had a professional company come to Washington to clean up the mess, as there is water and soil mixed in the cafeteria.

"It's a mess," Wolleat said, but it will be cleaned up before the students come back Monday.

"We're keeping our fingers crossed that we don't have anymore issues. Let's hope it doesn't rain for a few days now and we get some steady melt of the snow. We hope to see the warmer weather next week."

Wolleat said the water at BHS and Forestview was minor and was most likely already cleaned up, as he was talking to the Dispatch on the telephone Thursday morning. Wolleat said the flooding issues are affecting everyone. He said he heard the ground is frozen 8-10 feet, making it difficult for runoff to infiltrate into the ground and the stormwater basins are freezing up.

"We're not used to having these types of rainstorms at this time," Wolleat said. "This is not a good situation."

What Brainerd/Baxter are seeing

Aside from the issues at a couple of the school buildings, Brainerd City Engineer Paul Sandy said city storm drains have been doing their jobs, preventing city streets from succumbing to much localized flooding.

"We had a pretty good handle on the storm drains (Wednesday)," Sandy said over the phone late Thursday morning, noting crews went out right away that morning to work on a few storm drains holding up water and then sent plows out to scrape the slush off the streets.

"We are getting some concerns about slush and some things on the streets since the rain loosened everything up, mostly in the alleys," Sandy said, noting most calls to the city in the last couple days dealt with concerns about the excessive amounts of slush in the alleys.

"We had to kind of take a different approach to do our alleys because we didn't want to plow people in with a bunch of slush," he added. "So we're trying to use a loader with a bucket to get them cleared out somewhat so that water drains out of them because the slush is holding all that water back."

In an effort not to push the slush into residents' yards, Sandy said crews are trying to push it down alleys before scooping it up onto the ends of boulevards.

"It's tough to get around," Sandy acknowledged, alerting residents of difficulties they may have getting parked vehicles out of the alleys before, or even after, plows go by.

"Because, frankly, it's impossible to get them cleared out really well," he said. "It's going to be messy for a long time."

He advised parking on streets after they're cleared instead of in alleys for the time being.

"The alleys might be a little bit impassible while the snow melts," Sandy added. "And we're trying to just get them to drain, more or less, so that we don't run into a bunch of soft alleys here in the spring."

Beyond potholes and ditches filling with water, the situation is stable and being monitored in Baxter, City Administrator Brad Chapulis and Public Works Director Trevor Walter said during a conference call.

"The reality is that we have a perfect storm. We've had extreme changes of temperature that's been expediting the melt along with the precipitation. We still have solid ground where the water can't penetrate. So there should be localized flooding in just about every place," Chapulis said. "But, we've been working for about two weeks to stay ahead of this by having our street department trying to open up and make sure there's no obstructions to our catch basins."

"It's been localized flooding," Walter added. "Not where the street's been submerged underwater or people having their houses and garages flooded."

While there were sporadic concerns raised by residents during the last 48 hours or so, Chapulis said, so far the extent of the flooding is mostly confined to roadway infrastructure in the form of potholes, not damage to individual properties or buildings-at least for now.

Crews are working to ensure excessive amounts of water runoff into nearby ditches, Walter said, but the concern is there's enough melting snow and rainfall to overwhelm these ditches.

With current conditions projected to continue going forward, he noted, that's a real possibility.

"If the ditches fill up, then where does the water go?" said Walter, who noted city employees are working diligently, both Thursday into Friday at the least, to quell the surge. "If it does keep going, I think we could have some serious flooding. Hopefully not."

As for Red Sand Lake or White Sand Lake residents, there's no indication flooding is a realistic possibility along those stretches. These areas are constantly monitored by city staffers, Walter and Chapulis both noted, and water levels have not reached a point at any time in the last two weeks for flooding to be imminent.

What Crow Wing County is seeing

Crow Wing County Emergency Management Director John Bowen was out of the office Thursday and not scheduled to return to work until next week, but Capt. Joe Meyer of the sheriff's office answered questions on Bowen's behalf.

"What the county is doing to prepare for the flood situation, I'm not aware of any drastic measures we've taken so far. ... We're just in kind of a waiting pattern," Meyer said Thursday afternoon. "The county highway has been monitoring culverts, low areas, to see if anything is backing up. We have not been made aware of anything at this point. I checked with dispatch this (Thursday) morning, to see if there was anything reported overnight and there was not.

" ... We've had some minor water issues within our complex, here, with groundwater coming in. But we haven't had any reports of any roads flooding, or culverts or river issues as of yet, so we are standing by and well prepared for any emergencies that should arise."

Nick Eades is the owner/manager of Brainerd Ace Hardware on Washington Street. He believes in disaster preparedness, and his store also has items for sale to help deal with the aftermath.

"We had some sandbags go out. Currently, a lot of the submersible pumps, a lot of hoses going out the door-things like that," Eades said. "... Sump pumps are failing and people are replacing those, so it's been a good day for all kinds of pumps and pump accessories. ... When you have flooding like this, those sump pumps are working all the time because they're continually filling up, so those are running hard and so people are replacing those when they're failing because they're not made to really run all the time."

Eades said a man bought a submersible pump because his loading dock was filled with water from a combination of rain and warmer temperatures thawing the accumulated snow.

"As far as heading off the problem, that would have been clearing snow away from the house and making sure your roof was prepared early. ... Unless you've cleared all that snow away, it's just going to act as a curb and focus the water back towards the house," Eades said. "If you didn't have gutters, and you didn't get the snow away from the house, the water comes off of the roof, it hits that snowbank and rolls to the inside instead of the outside, and it just forces it in, so those snow piles are actually acting like curbs and they're keeping that water in."

The science behind it

According to the U.S. Geological Survey, when rain or snow falls onto the earth, it just doesn't sit there, it starts moving according to the laws of gravity. A portion of the precipitation seeps into the ground to replenish Earth's groundwater. Most of it flows downhill as runoff. Runoff is important in that not only does it keep rivers and lakes full of water, but it also changes the landscape by the action of erosion.

Frozen soils typically reduce infiltration rates, and may completely prevent water from entering. The book "Science and Issues Water Encyclopedia" reports precipitation falling as snow is stored until snowmelt, when a large pulse of runoff may be generated. Runoff occurs only after the entire snowpack has reached 32 degrees, some melting has occurred and pore spaces between snow grains can no longer hold all the water supplied.

The rate of snowmelt depends on heat inputs into the snowpack through solar radiation and via water from melting and rainfall moving through the snow. The soil surface underneath the melting snowpack may become saturated, such that runoff flows through the base of the snowpack toward streams. To learn more, go online to https://bit.ly/2TLkeBA.

According to the National Weather Service, rain will usually not add much heat to the process of melting snow. At 40 degrees, 1 inch of rain will only produce a tenth of an inch of added water from snow melt. At the same time frozen ground will result in more of the available water running off directly to streams. If rain falls for three to five consecutive days with daily maximum temperatures only in the middle 30s around the same time, it may result in ice breakup. Ice jams may occur within a day or two after the rain begins.