With a major storm forecasted to begin impacting much of Ontario late Friday afternoon and throughout the weekend, the Grand River Conservation Authority has issued a flood warning for the entire watershed.
The GRCA says there is limited ice cover on rivers and streams at this time and the risk of ice jam flooding – such as the flooding that led to an evacuation of homes in Brantford two years ago – is considered low with this event. GRCA’s major reservoirs at Belwood, Conestogo, Guelph, Luther, Woolwich, Laurel, and Shade’s Mills will be used to manage runoff from this event and reduce flooding downstream of these reservoirs.
Recent estimates say up to 50 millimetres of rain, possibly the freezing kind, could fall throughout the Grand River watershed, but the GRCA’s latest statement says “there is still a great deal of uncertainty with respect to how much of this precipitation will fall as rain before transitioning to freezing rain as temperatures fall through the day on Saturday.”
“It is expected that much of the northern Grand River watershed (north of Elora) will see a prolonged period of freezing rain, while the southern watershed (south of Cambridge) will receive heavy rainfall. The central portion of the watershed (Cambridge to Elora) is expected to see a mix of heavy rain and freezing rain for much of this event. How this precipitation falls will greatly impact how local waterways respond.”
Communities along the Grand River through the southern watershed, including Paris, Brantford, Caledonia, Cayuga, and Dunnville, should anticipate flooding in low-lying areas that typically experience spring flooding. Flows in the southern Grand River watershed will peak late Sunday and through the day on Monday.
Flows in the Grand River through Brantford are expected to overtop Gilkison Street. Brantford flood coordinators are requested to close this area and monitor conditions.
The wind could also gust up to 90 km/h, particularly closer to Lake Ontario.
The public is reminded to exercise extreme caution around all water bodies. Banks adjacent to rivers and creeks are very slippery at this time and, when combined with current weather conditions, pose a serious hazard. Parents are encouraged to keep their children and pets away from all watercourses.