Fargo Mayor Tim Mahoney pulled out a big three-ring binder after forecasters delivered the bad news on Thursday — winter storms coming this weekend and next week are raising the odds of major spring flooding there and in river towns throughout Minnesota.
Like Mahoney, who was calculating how many sandbags will be needed to protect homes and businesses, leaders of towns from the Red River Valley down to those along the banks of the Mississippi, Minnesota, Crow, St. Croix and Cannon rivers are bracing for spring flooding after the National Weather Service's latest update.
Last week, forecasters warned of a higher-than-usual chance of spring flooding. On Thursday, they upped the odds for major flooding in many areas.
Over the past two weeks, steady snowfall has added another inch of water to the deep snowpack that blankets most of the state, according to Craig Schmidt, senior hydrologist with the National Weather Service in Chanhassen.
The heavy, wet snow expected to fall this weekend and a storm next week that may deliver rain and snow will add even more, he said.
Cold weather to date has kept much of the snowpack from melting, leaving more snow on the ground heading into the spring thaw.
"This year has been different because a lot of times it would snow early in the year and then we would lose some. Snow some more, lose some," Schmidt said. "Every flake that's fallen is pretty much still out there."
To calculate how much, weather observers across the state trudge outside to collect core samples of snow in a tube, measuring the snowpack's depth, then melting it to see how much water it will produce. The water from the snowpack amounts to 2½ to 4½ inches across a large swath of the state, with some areas reporting 5 to 6 inches, Schmidt said. "This ranks near historical high levels for early March," he said in his report.