The big meltdown
Lots of it.
And lots of water looking for a place to go.
A warm spell starting Saturday will push temperatures to near 40 degrees, with highs near 50 by Monday.
What snow doesn’t melt will dissolve under rain Saturday and Monday, said Chris Franks, a meteorologist with the National Weather Service in Sullivan. Weather models haven’t agreed on how much rain will fall, but Franks said it could be up to one-half inch.
And be prepared for fog.
With warm winds blowing across snow still on the ground, fog is likely through Monday, Franks said.
Janesville received 28.5 inches of snow in December, making it the second-snowiest December since 1948. About 9 inches of snow remain on the ground today at Janesville’s Wastewater Treatment Center.
But that melting snow will need somewhere to go, and Franks said it could create flooding in problem areas.
“I would think a lot of the area should be on a heightened alert for updates in the forecast,” he said.
The recent cold snap might have accumulated ice on rivers. The anticipated warm weather might not quite melt it but break it up and cause ice jams, he said.
The rule of thumb is usually 10 to 15 inches of new snowfall equal 1 inch of water, he said. But snow on the ground has been packed and is heavier, he said.
Fortunately, some of the water might be able to soak in because the ground isn’t frozen everywhere.
The snow cover has been a “good insulation blanket” for the ground, said Norm Tadt, senior conservationist for Rock County Land Conservation.
Ground near sidewalks and under driveways is frozen, but it is not frozen in the middle of fields, he said. That should “get a lot of water moving through the soil,” he said.
Chrissy Allard of Badger Basement Systems in Fort Atkinson said her business is anticipating plenty of calls this weekend for basement flooding.
The slight melt-off already has increased business with homeowners who have water coming in through walls, she said.
People with pumps should shovel out the discharge area so water doesn’t freeze and back up the system, she said.
Janesville city workers have been clearing catch basins and storm sewer inlets to prevent street flooding, said Mandy Bonneville, assistant operations director. People who see such areas blocked by snow can either clear it themselves or report the location to the city by calling (608) 755-3110.
“Typically the river reaching high levels isn’t a problem this time of year,” she said.
The city is not planning for sandbagging in low areas, she said, “but of course anything can happen.”
Farm runoff should be kept to minimum
If Rock County farmers have done their job, runoff from this weekend’s warm-up should be kept to a minimum.
Farmers in Rock County “get it,” said Norm Tadt, senior conservationist for the Rock County Land Conservation Department.
“Our farmers are ahead of the curve,” Tadt said.
In the city, anything in streets and gutters has a straight route to the closest stream and eventually the Rock River. In the country, water will flow the same way off farm fields—even flat ones, Tadt said.
“Melting snow is not pure,” Tadt said. “It’s not clean when it comes out of the sky, and it’s not going to get any cleaner. Sediment, nutrients, whatever it picks up is going right into the stream.”
By nutrients, Tadt means fertilizer or manure, which are good for crops but bad for lakes and rivers.
The county helped 11 farmers sign contracts in 2007 to get federal cost sharing for nutrient management plans. Those plans dictate how, where and when farmers will spread manure or fertilizer in order to minimize waste and bills.
Some of the plans dictate how a farmer plants a field. Here are some popular choices:
-- No-till planting is just what it sounds like. Farmers don’t plow a field after harvesting a crop. That saves fuel costs and increases ground cover.
“Think of those rains that kind of hurt when they hit your skin,” Tadt said. “When those drops hit bare soil, they bounce. And every little droplet carries soil away with it.”
-- Terrace planting. Fields are built like steps on the side of the hill. A 600-foot hill might have terraces at 200, 400 and 600 feet, Tadt said.
“That way the raindrop that hits at 600 feet only has to flow 200 feet. It doesn’t have to pick up so much speed.”
-- Contour cropping. If you walk through a cornfield, you’ll see the soil piled in little ridges at the base of the corn rows. If you plant the corn across the slope of a hill, it will slow water down, rather than providing a slide for it to rush down, Tadt said.
—Ann Marie Ames
Last updated: 3:07 pm Thursday, December 13, 2012