FLOOD WARNING – Lake Talon and Mattawa River subwatershed

FLOOD WATCH – Other Areas

(North Bay April 24, 2023). A Flood Warning remains in effect for the Lake Talon and Mattawa River subwatersheds according to the North Bay-Mattawa Conservation Authority (NBMCA). A Flood Watch is in effect for all other areas of the North Bay-Mattawa watershed.

“Recent rainfall from April 20 to 22 caused water levels to rise on watercourses across the North Bay-Mattawa watershed,” said Angela Mills, NBMCA Duty Officer. “Water levels in Lake Talon and watercourses in the Mattawa River watershed have remained high over the last few days. The Wasi River and La Vase River have also experienced high water levels.” Most watercourses have now started to decline in the last twenty-four hours. Note that water levels on Lake Nipissing are still within the normal range for this time of year and shoreline flooding is not expected at this time.

The Ministry of Natural Resources and Forestry operates several dams that control lake levels within the Mattawa River watershed. The water level on Lake Talon is 35 cm above the high limit, while Turtle Lake and Lake Nosbonsing are at or slightly above their high limits. The water level of Lake Chant Plein is now below its high limit and has decreased 16 cm since April 17. Flows downstream of these lakes, as well as other parts of the Mattawa River watershed, remain high.

The Ottawa River water levels are managed by upstream dams and reservoirs operated by provincial and federal governments. The Ottawa River water level at Mattawa has increased steadily over the past week and is up 158 cm since April 17. The Ottawa River Regulation Planning Board’s four-day forecast shows levels at Mattawa remaining at current levels.

A snow survey conducted on April 24 recorded no snow after significant snowmelt. Some isolated patches of snow remain in shaded and forested areas. This is down from the average of 81 mm water storage that was measured on April 14. Ice cover on area lakes is deteriorating with large open patches.

Weather conditions forecasted for this week have daytime highs between 3 and 14 ºC, and overnight lows expected to range from -5 to +6 ºC. Small amounts of rain or snow are forecast through Wednesday (April 26). Long-range forecasts indicate a potential rain event Saturday into Tuesday (May 2) bringing 40 to 50 mm of rain.

For comparison, when river-based flooding occurred in April 2019, the snowpack water content was 15 mm (measured April 24, 2019). Rainfall of 24.2 mm was measured April 26, 2019. Daytime and overnight temperatures were above freezing.

Residents, especially those in low lying areas, are encouraged to monitor the conditions as they develop, and prepare accordingly. Shorelines of creeks and rivers will be very slippery at this time and, when combined with cold open water, pose a serious hazard. The public is encouraged to keep children and pets away from watercourses and off waterbodies,” said Chitra Gowda, NBMCA CAO.

As part of the NBMCA Flood Forecasting and Warning Program, staff will continue to monitor weather and watershed conditions and update this message based on the changing weather/streamflow conditions. Staff remain in contact with municipalities and other partners as required.

The general public is advised of these messages through the www.nbmca.ca website with the flood status icon and a link to information about current conditions. NBMCA also circulates these messages to local media and social media, posting on Twitter (@theNBMCA), Facebook (@theNBMCA) and Instagram (nbmcainfo).                 

This message will be in effect until (or updated before) Friday, April 28, 2023 at 2:00 pm.



Angela Mills, Duty Officer, cell: 705-497-4668
Chitra Gowda, CAO, cell: 705-477-0372

Terminology: Notification Levels

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