The following is a description of the 1996-97 floods from a U.S. Geological Survey Scientific Investigations Report published in 2005.
The harsh winter of 1996-97, combined with the 1997 spring floods, caused the worst natural disaster in recent history for North Dakota, eastern South Dakota, and western Minnesota. Above-normal snowfall in central and eastern North Dakota during the winter of 1996-97 and a blizzard on April 5-6, 1997, caused the worst flooding in the Red River of the North and Missouri River Basins in more than 100 years.
The heaviest snowfalls occurred along the main stems of the Red River of the North and the Missouri River and were about 300 percent greater than normal. About 117 inches ofsnow were recorded in Fargo, 96 inches in Grand Forks, and 101 inches in Bismarck (National Oceanic and Atmospheric Administration, 1996a). Elsewhere in the region, snowfalls were well above seasonal averages. Melting of the snowpack and thawing of ice began in late March on rivers and streams in the southern and western parts of the State. Flows were inhibited by a blizzard that occurred on April 5-6, 1997. The blizzard brought a severe drop in temperatures, winds up to 70 miles per hour, and up to 2 feet of snow with drifts many feet higher in several areas. In southeastern North Dakota, the blizzard was preceded by wind-driven rain and sleet. The wind and ice toppled trees and power lines, leaving thousands of people without power for days. Thousands of people were forced to flee their homes, some permanently, as floodwaters and severe weather caused over $5 billion in damage to the region (National Oceanic and Atmospheric Administration, 1997b).
The Red River of the North is one of the few rivers in the United States to flow directly north into Canada. The basin flood plain lies in a glacial lakebed and is relatively flat (less than 0.5-foot drop in elevation per mile in the reach downstream from Grand Forks, North Dakota). Because of the flat basin, the shallow river channel, and the northerly flow, the timing of spring thaw and snowmelt can greatly aggravate flooding in the basin. Snow and ice in the headwaters of the Red River of the North begin to melt first, when areas downstream remain largely frozen. The melt pattern can cause ice jams to form, and substantial backwater can occur as flow moves northward toward a still-frozen river channel.
Two peak stages occurred in Wahpeton, which is located in the southern part of the Red River of the North Basin. On April 6, 1997, the stage of the Red River of the North at Wahpeton
(streamgage 05051500, table 35) was 19.42 feet, which is 1.47 feet higher than the record set in 1989. Because of the additional
moisture from the April 5-6, 1997, blizzard, a record flow of 12,800 cubic feet per second and corresponding stage of 19.25 feet was recorded 9 days later. On April 17, 1997, the peak stage of the Red River of the North at Fargo (streamgage 05054000, table 35), about 96 river miles north of Wahpeton, was 39.57 feet, and the peak flow was 28,000 cubic feet per second.
On April 18, 1997, the peak stage at Fargo was 39.72 feet, which exceeded the record set 100 years earlier, and the peak flow was 27,700 cubic feet per second.
High flows continued to move downstream in the Red River of the North. On April 18, 1997, the peak stage of the Red River of the North at Grand Forks (streamgage 05082500, table 35) was 52.04 feet, which is 1.84 feet higher than the record set in 1897, and the peak flow was 137,000 cubic feet per second. The peak flow was unusual because it resulted from the convergence of flows from the Red Lake River in Minnesota, flows from the main channel, and breakout flows from the Red River of the North that were conveyed by old Red River of the North oxbows. Breakout flows occurred upstream from Grand Forks when plugs in the upstream end of the oxbows either were overtopped or washed away, which caused a flow of about 25,000 cubic feet per second to arrive at the confluence of the Red Lake River and the Red River of the North at Grand Forks. The flow of 25,000 cubic feet per second coincided with the peak flow of the two rivers. To compound problems in Grand Forks, a fire on April 19, 1997, demolished several buildings in the flooded city. The flooding made it extremely difficult for firefighters to reach the fires and put them out. Except for emergency
personnel, Grand Forks and its sister city, East Grand Forks, Minnesota, were completely evacuated at this time.
On April 24, 1997, the peak stage at the Red River of the North at Drayton (streamgage 05092000, table 35) was 45.55 feet, which is 1.89 feet higher than the record set in 1979, and the peak flow was 124,000 cubic feet per second. At the Pembina River at Neche (streamgage 05100000, table 35), the peak stage was 24.51 feet, which is 0.87 foot higher than the record set in 1979, and the flow was 12,800 cubic feet per second.
Six days later, the peak flow was 15,100 cubic feet per second, and the stage was 24.20 feet. On April 27, 1997, USGS personnel measured 141,000 cubic feet per second in the Red River of the North at Pembina (streamgage 05102490, table 35), which is located about 2 miles upstream from the international boundary with Canada. The previous maximum discharge of this century at the Canadian streamgage, Red River at Emerson, Manitoba (streamgage 05102500), located about 1 mile downstream from the border was 95,500 cubic feet per second on May 13, 1950.
Perry, C.A., 2005, Summary of Significant Floods in the United States and Puerto Rico, 1994 Through 1998 Water Years: U.S.
Geological Survey Scientific Investigations Report 2005-5194, 327p.