Table 2. Hazard Profile of 2011 Flood Events in Fargo ND and Minot ND.
| HAZARD DESCRIPTION AND INDICATORS | FARGO ND | MINOT ND | |
|---|---|---|---|
| Disaster Type | Natural Disaster: Hydrological/ River Flooding |
Natural Disaster: Hydrological/River Flooding |
|
| Geographic Features | Red River Valley is the lakebed of prehistoric Glacial Lake Agassiz Flat terrain Flooding area is vast Floods: slow-moving and shallow |
Souris River valley is deep and narrow: carved by catastrophic glacial meltwater drainage. Waters are confined by the high valley walls Floods: deep and fast-moving |
|
| Contributory Climatological Events |
Very wet Autumn 2010 2010/2011 snowfall twice the climatological average Late Spring 2011 snowmelt Moderate to heavy rainfalls |
2010/2011 snowfall above climatological average Above normal snowpack upstream in Canada and North Dakota Above normal Spring 2011 rainfall in May/June |
|
| Upstream FloodControl | Upstream drainage area of 5,400 km2, with upstream flood storage capacity of 206 billion cubic meters | Upstream drainage area 8,370 km2, with a flood stage storage capacity of 860 billion cubic meters Extensive upstream flood control (reservoirs/dams) in Canada and North Dakota. Flood control directed by agencies from two nations. Meltwater and precipitation overwhelmed storage capacity of upstream flood control structures Flows overtopped flood protection structures in Minot |
|
| Scale/scope of flooding | Expansive overland flooding of rural farmlands around Fargo Minimal flooding in Fargo |
Most destructive flooding on record 4,100 homes inundated |
|
| Magnitude of water flow | Peak flow rate | 740 m3/s at crest on April 9, 2011 Average: 22 m3/s |
730 m3/s at crest on June 26, 2011 Average: 4.3 m3/s |
| River crest | April 9, 2011: 11.8 m (6.3 min above flood stage of 5.5 min) |
June 25, 2011: 7.4 m (3.1 min above flood stage of 4.3 min) |
|
|
2011 Rank |
4th highest crest in recorded history (record crest: 2009) |
Highest crest in recorded history (recording commenced in 1904) |
|
| Duration | Days at/above flood stage | 144 d above 5.5 min during March 30-August 27, 2011 (except June 13–16, June 19–21) 26 d above 9.1 min (“major” flood stage) during April 6-May 1, 2011 |
113 d above 4.3 min during April 10-July 31, 2011 |
| Frequency | Fargo is in a “wet cycle” Flood stage has been exceeded every year since 1993 Flood stage exceeded 29 times between 1903 and 1992 |
Souris River floods periodically but not regularly. The flood in 2011 was “historic” rather than usual and predicted | |
| Predictability | Based on almost two decades of river rises exceeding flood stage, Fargo predicts and anticipates annual flood threats | Flooding is sporadic and much less predictable. The very heavy snowfall and deep snowpack provided a warning of possible flooding | |