A variety of factors are considered when assessing flood risk. While the recent snowfall in the Minot region was substantial and the forecast for additional precipitation indicates the potential for considerable moisture, the risk of widespread flooding in the Mouse River basin remains low.

The figure below is from the National Oceanic and Atmospheric Administration’s (NOAA) National Operational Hydrologic Remote Sensing Center (NOHRSC) website. This is the modeled snow water equivalent within the region as of today. While a portion of the watershed above Minot has 2 to 4 inches of snow water equivalent on the landscape because of the recent storm, much of the watershed, including the portion in Saskatchewan has less than one 1 inch of snow water equivalent on the landscape.

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By comparison, the figure below represents the snow water equivalent on the landscape just before the spring melt in 2011. At that time, much of the watershed above Minot had 4 to 6 inches of water on the landscape. So by comparison, even though the recent snow event was considerable, the amount of water on the landscape as compared to our last flood event is low.

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Additionally, the ground is mostly thawed beneath the recent snow cover. This is great news for our agricultural producers, as much of the water will likely soak into the soils as the snow melts. In fact, much of the snow that has melted has done so from the ‘bottom up’ due to the current ground temperatures.

 

Also, it’s important to note that our region has been in a prolonged drought for approximately two years. While the latest US Drought Monitor maps were issued prior to the recent snow storm (hopefully the next version shows a further transition away from the drought), the maps show that the Mouse River region as generally abnormally dry (yellow) to extreme drought (red). This is a strong signal that the underlying soils will have significant infiltration capacity, especially if the melt is prolonged due to relatively low air temperatures.

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Some have questioned the status of the reservoirs on the Mouse River watershed above Minot. There are three large reservoirs on the Mouse River watershed with available flood control storage. The levels of the reservoirs in Saskatchewan may be monitored through the Saskatchewan Water Security Agency. The level of Lake Darling may be monitored through the National Weather Service Advanced Hydrologic Prediction Service.

 

Currently, the level of Rafferty Reservoir near Estevan is 548.2 meters. The targeted water supply level for Rafferty is 550.5 meters. The maximum allowable flood level in Rafferty is 554.0 meters. Rafferty Reservoir is currently 5.8 meters (19.0 feet) below the maximum allowable flood level.

 

Currently, the level of Grant Devine (formerly Alameda) Reservoir is 561.1 meters. The targeted water supply level for Grant Devine is 562.0 meters. The maximum allowable flood level in Grant Devine is 567.0 meters. Grant Devine Reservoir is currently 5.9 meters (19.4 feet) below the maximum allowable flood level.

 

Currently, the level of Lake Darling is 1594.8 feet. The targeted water supply level for Lake Darling is 1598.2 feet. The maximum allowable flood level in Lake Darling is 1602.2 feet. Lake Darling is currently 7.4 feet below the maximum allowable flood level.

 

With 19.0 feet of available storage in Rafferty Reservoir, 19.4 feet of available storage in Grant Devine Reservoir and 7.4 feet of available storage in Lake Darling, the reservoirs on the basin are well-positioned to store runoff occurring due to the recent and forecast snow and rain events.

* This information is current as of 4-18-2022. For the most recent models, visit NOHRSC's Interactive Snow Map.