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Published February 20, 2010, 12:00 AM

Prepare for battle: Risk grows of repeating 2009 flood

Three weeks ago, National Weather Service forecasters said conditions for major spring flooding in the Red River Valley were like a keg of dynamite. Things have gotten worse.

By: Helmut Schmidt, INFORUM

Three weeks ago, National Weather Service forecasters said conditions for major spring flooding in the Red River Valley were like a keg of dynamite.

Things have gotten worse.

“The powder’s dry. The power keg is bigger, and the fuse is a bit shorter,” meteorologist Greg Gust said Friday at a news conference at Fargo’s City Hall.

There’s now a 25 percent chance of a Red River flood in Fargo to match last year’s record 40.84 feet, Gust said.

“That still is an incredible risk” to deal with, Gust said.

Fargo, West Fargo and the North Dakota towns of Harwood, Abercrombie and Lisbon all have a greater than 90 percent risk of reaching or exceeding major flood stage, the weather service flood outlook said.

The Red has a 96 percent chance of exceeding the major flood stage of 30 feet in Fargo-Moorhead. That’s up from an 86 percent chance in the Jan. 29 flood outlook.

There’s a 30 percent chance the Red River in Fargo will exceed 40.3 feet, a 50 percent chance it will exceed 38.6 feet and a 70 percent chance it will exceed 37 feet, Friday’s outlook said.

The biggest reason is the high water content in the snowpack in southeastern North Dakota, Gust said, but other factors also come into play:

  • Fall soil moisture levels were high.

  • Stream flows are high and rivers froze at higher levels than in fall 2008, an indicator of too much water in the system.

  • Frost is deep and rock hard, which means all the water in the snowpack will be available for runoff.

  • River ice is deep, which can add to flooding caused by ice jams.

  • Moisture levels are approaching last spring, when the area received the equivalent of more than 14 inches of water over the winter. The norm is about 7 inches.

    “Given the snowpack we have in place, we don’t have nearly the wiggle room that we had in place last year,” Gust said.

    The wild cards are how much precipitation falls, and how fast the thaw arrives. Gust said.

    “The prospects for a gentle spring season appear remote,” said Mark Frazier, the meteorologist in charge of the weather service office in Grand Forks. He encouraged everyone to prepare for the flood season.

    Major flooding is expected on the Minnesota tributaries of the Red, but chances of hitting 2006 or 2009 flood levels are low, Gust said. But North Dakota cities on the Sheyenne and Wild Rice rivers could face flooding to rival last year’s, thanks to the moisture-laden snowpack.

    Along the Sheyenne below Valley City and moving into Lisbon, Kindred and Harwood, “you’re looking at predictions that pretty much rival 2009,” Gust said.

    Cooler and wetter

    Gust said the eight- to 14-day outlook calls for near-normal temperatures. No significant moisture is expected until March 3-5.

    Forecasters predict a cooler and wetter spring than normal, with another half inch to 1 inch of rain or its equivalent in snow.

    Some observers argue it will take significant rain or a fast thaw to tip the Valley into a record flood fight.

    “We’re not staging this event to get us a diversion,” Fargo Mayor Dennis Walaker joked.

    He said the flood threat doesn’t yet match last spring’s profile.

    “I’m not going to get worried until it actually happens,” Walaker said.

    He said Fargo will work to make 1.5 million sandbags, and is coordinating with schools and the National Guard on planning.

    “As far as I’m concerned, it was a miracle that we survived the flood of 2009,” Walaker said.

    Gust said this spring’s rains don’t need to be as heavy or the melt as fast as last year to produce a monster flood. To avoid major flooding would require a dry spring, he said.

    “In the scenario we have set up for us, we don’t have much wiggle room,” Gust said. “Inevitably this snow has to go, and its likelihood of its sinking into the soil is not high.”

    The next flood forecast will be released March 5.

    Readers can reach Forum reporter Helmut Schmidt at (701) 241-5583

    Forum reporter Mike Nowatzki and news editor Steve Wagner contributed to this report.