(North Bay April 10, 2023). With the forecasted warm temperatures and anticipated significant snowmelt, water levels in creeks, rivers and lakes may rise. The North Bay-Mattawa Conservation Authority (NBMCA) is issuing a Flood Watch for the entire watershed to notify that the potential for localized flooding exists especially in low lying areas, as the snowmelt progresses.
“Weather forecasts show warmer temperatures with minimal rain this week. The sudden shift in weather to very warm temperatures, as high as around 20 ºC, is expected to trigger significant and rapid snowmelt,” said Angela Mills, NBMCA Duty Officer. “Urban watercourses in North Bay will respond more quickly to the snowmelt. Watercourses in rural areas may also experience high water levels”, Mills added.
The snowpack water content is very high in the North Bay – Mattawa watershed, ranging between 181 mm and 238 mm of water equivalent (measured on April 6, 2023). This is an increase of 6 to 54 mm since the previous survey (March 31). Snow depths range between 51 and 60 cm in the NBMCA watershed, an increase of 5 to 10 cm since the previous survey.
The Chippewa Creek water level is fluctuating by around 20 cm in response to the alternating melting and freezing of the snowpack, influenced by daily high and low temperatures. Water levels on Wasi River increased by 31 cm, La Vase River increased by 23 cm, and Lake Nipissing increased by 6 cm since April 4, 2023. Water levels on the Ottawa River main stem from Mattawa to Montreal are expected to rise, per the Ottawa River Regulating Committee (https://ottawariver.ca/latest-news/). Lake-based flooding around Lake Nipissing is not expected at this time.
For comparison, when river-based flooding occurred in April 2019, the snowpack water content was 123 mm (measured April 15, 2019). Rainfall of 31.8 mm was measured April 18, 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.
“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,” said Chitra Gowda, NBMCA CAO. 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) Monday, April 17, 2023 at 4:00 pm.
Angela Mills, Duty Officer, cell: 705-497-4668
Chitra Gowda, CAO, cell: 705-477-0372