Qualla: 2011 Assiniboine River Flood

2011 Assiniboine River Flood: Introduction

Thu, 05 Feb 2026 00:00:00 GMT

Photo credit JohnBuermeyer, CC0. Everyone was watching the wrong river. In the spring of 2011, Manitoba braced for flooding along the Red River, the usual suspect in a province defined by its flatness and its water. But the Assiniboine, flowing east through the Westman Region of Manitoba and Saskatchewan, had other plans. Fed by relentless rainfall that began in the fall of 2010 and continued through a winter of heavy snow, the Assiniboine swelled to levels not seen in three hundred years. By the time the river peaked at Brandon, it was running sixty percent higher than the previous record set in 1923. Across Manitoba, 7,100 people were driven from their homes, and governments at every level spent close to one billion dollars fighting the water and compensating those it displaced.

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2011 Assiniboine River Flood: A Slow-Motion Catastrophe

Thu, 05 Feb 2026 00:00:00 GMT

Photo credit JohnBuermeyer, CC0. The 2011 flood announced itself months before the crisis peaked. Major rainfall events in the fall of 2010 saturated the Assiniboine River watershed, and wet conditions persisted through the winter. Engineers emptied the Shellmouth Reservoir during the winter of 2010-2011, prepar...

Image: JohnBuermeyer | CC0

2011 Assiniboine River Flood: Brandon Under Siege

Thu, 05 Feb 2026 00:00:00 GMT

Photo credit JohnBuermeyer, CC0. Brandon, Manitoba's second-largest city, had time to prepare. Workers built earthen dikes alongside sandbag and Hesco bastion barriers well in advance. It was not enough to prevent a state of emergency. The Assiniboine peaked at Brandon at a level sixty percent above the previous...

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2011 Assiniboine River Flood: The Breach at Hoop and Holler Bend

Thu, 05 Feb 2026 00:00:00 GMT

Photo credit JohnBuermeyer, CC0. Downstream of Brandon, the math was dire. The Manitoba government forecast that between 54,000 and 56,000 cubic feet per second of water would reach the Portage Diversion reservoir near Portage la Prairie. The Diversion channel, designed to drain overflow into Lake Manitoba, coul...

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2011 Assiniboine River Flood: The Lake That Kept Rising

Thu, 05 Feb 2026 00:00:00 GMT

Photo credit JohnBuermeyer, CC0. The Portage Diversion channeled enormous volumes of Assiniboine floodwater into Lake Manitoba, and the lake responded by rising far beyond its normal operating range. The 2011 diversion far exceeded the volume sent into the lake during the 1976 Assiniboine flood. Residents at Del...

Image: JohnBuermeyer | CC0