Fargo area to see major flooding as March forecast shows no mercy
FARGO — Two winter storms bearing down on the Fargo-Moorhead area over the next seven days are expected to increase flood threats, leaving the Red River Valley at the mercy of how fast moisture-packed snow melts this spring, National Weather Service meteorologists said Thursday, March 7.
But work that's been done in the last decade along the river in Fargo “eliminates or significantly reduces our emergency measures that we need,” said Nathan Boerboom, an engineer for the city.
Above-normal snowfall has hit the region and is expected to continue into an “unmerciful” March, meteorologists said in an updated spring flood outlook. Two storms — the first on Saturday afternoon and the second likely Wednesday — are forecast to pummel the valley.
“The risk for significant snowmelt flooding has further increased, running well above long-term historical averages across the Red River and Devils Lake Basins,” meteorologists said.
The storm set to hit Saturday afternoon could bring 2-5 inches of snow to Fargo-Moorhead, WDAY meteorologist Summer Schnellbach said.
That could drop an additional inch of moisture on the area, weather service meteorologist Greg Gust said. The metro area already has roughly 3 inches of moisture in its snowpack, he said.
Above-normal moisture, snowpack and frost depth are not extreme yet, but the two storms could push moisture levels much higher, Gust said.
“The spring thaw cycle is running late, and that favors a fast thaw cycle as we get later into March and early April,” he said, adding that the overall risk for flooding is up.
However, precipitation levels ahead of the 1997 and 2009 floods were between 5 and 7 inches throughout the valley. “We have nothing near those levels yet,” Gust said.
The Red River in Fargo likely will reach a crest of at least 31 feet deep, above the major flood level of 30 feet, according to the weather service. There's a 50 percent chance the Red could be almost 35 feet deep, and a 5 percent chance of reaching 39 feet, just short of the record crest of 40.8 feet in 2009.
The city would start building temporary clay levees after the river hits 35 feet, while sandbagging could start after 37 feet, Boerboom said. Fargo officials will watch the forecast closely and prepare as potential hazards develop.
“It’s clear that we’re definitely going to get a reaction out of the river this year,” he said. “At low 30s, we should be fairly comfortable at that point.”
Much work has been done in recent years to remove homes from the floodplain, said Lisa Bode, governmental affairs director for Moorhead's Community Development Department. Some infrastructure, including pedestrian bridges and park shelters, may be impacted if the Red reaches 31 feet, but no homes would be in danger at that level, she said.
“The need for sandbagging has been greatly reduced,” she said.
Fargo already has tallied 49 inches of snow this season, above the normal of 37.5 inches for this time of year. But that's well below the total snowfall record of 83.4 inches for the 1996-97 season.
It's also below the 51.4 inches Fargo saw up to this point in the 2008-09 season. The total for that winter was almost 80 inches.
Wahpeton, N.D., has a 25 percent chance of seeing major flooding, but the Red should crest there at about 12 feet, according to projections. The record there was set in 1997 at 19.4 feet, but there is only a 5 percent chance the Red will hit 17.5 feet in Wahpeton.
Gust noted several bridges in the area, including Fargo-Moorhead’s former toll bridge and First Avenue North, could be affected or possibly close. Officials could order the construction of dikes along the river in several areas if it reaches 31 feet.
Floodwall features likely will be tested in the metro area, Gust said.
Snowmelt could cause overland flooding, as well as road, floodwall and bridge closures, across the region, Gust said. Railroads also could be impacted.
“There’s going to be water flowing, filling ditches, moving overland in most areas of this basin,” he said.
Southeast North Dakota and west-central Minnesota — mostly south of Interstate 94 — are at the greatest risk of seeing more than 6 inches of snow this weekend, according to the weather service.
Heavier snow amounts could track north toward Fargo, but the heaviest snow should stay to the south and east of the city, Schnellbach said.
“The greatest chance for 8 inches or more looks like just north of the North Dakota-South Dakota border, with again that highest potential around the Twin Cities down through Sioux Falls,” she said.
A winter storm watch is in effect from early Saturday morning through Sunday afternoon for southeast North Dakota and west-central Minnesota, the weather service said. Winds could gust as high as 45 mph in some places.
Winds likely will remain between 10 and 20 mph for the Fargo-Moorhead area, lighter than previously expected, Schnellbach said, noting that snowdrifts and blowing snow are still a concern with this system. Areas west of the valley could see stronger winds, she added.
It’s too early to say exactly where the second storm will hit and how much snow it will drop, but Wednesday “looks promising” for the storm to reach Fargo, Schnellbach said.
There is some good news in the forecast. Thursday likely was the season's last day of negative temperatures, the weather service and Schnellbach said. Highs are forecast to reach into the 20s and low 30s for the next week, the weather service said.
When the Red rises: Flood impacts at certain river levels
45 feet ... Top of VA Medical Center's flood wall (Fargo).
43 feet ... Top elevation of Fourth Street permanent levee (Fargo).
42 feet ... Top of emergency clay levee (Fargo, 2013).
40.84 feet ... RECORD FLOOD: March 28, 2009.
40 feet ... River is lapping at the base of the Hjemkomst Center (Moorhead). Top of emergency sandbag levee (Fargo, 2013).
37 feet ... Convent Bridge at 52nd Avenue South is closed (Fargo).
36.29 feet ... Clearance height of First Avenue bridge (Fargo).
36 feet ... Sandbagging starts if the river is forecast to rise above 38 feet (Fargo).
35 feet ... Actions taken to prevent storm sewers from backing up (Moorhead).
34.4 feet ... NP Avenue (Fargo)/Center Avenue (Moorhead) bridge clearance.
33 feet ... Begin diking to protect the Hjemkomst Center (Moorhead).
32.5 feet ... First Avenue North bridge closed for construction of temporary dikes.
31 feet ... First Avenue North underpass is closed (Moorhead).
30 feet ... MAJOR FLOOD: Flooding at Second and Third Avenue North; Second Street South closed between Main Avenue and Fourth Street; temporary dike constructed on Oak Street dike from 87th Avenue North to 11th Avenue North (Fargo). Water crosses entrance road to Gooseberry Mound Park (Moorhead).
28 feet ... Fargo-Moorhead's former toll bridge closed. Construction begins on the dike to protect sewage treatment plant if forecast is above 34 feet (Fargo).
25 feet ... MODERATE FLOOD: City parks and recreation areas along the river begin to flood (Fargo).
24 feet ... Second Street North closes between First and Sixth Avenue North for construction of temporary dike that protects City Hall if the river is forecast to rise above 31 feet (Fargo).
23 feet ... North Broadway bridge floods (Fargo).
22 feet ... North Broadway bridge is closed (Fargo).
19 feet ... Low-level dam south of Main Avenue is underwater (Fargo).
18 feet ... MINOR FLOOD: Elm Street between 14th and 15th Avenue North is closed (Fargo).
17.7 feet ... Sanitary sewers affected; pump station at Island Park is started (Fargo).
17 feet ... ACTION STAGE: Water rises to the edge of the bike path at El Zagal bowl along Elm Street North between 14th and 15th Avenue (Fargo).
Source: National Weather Service