With enough snowpack north of Greater Sudbury to trigger a resurgence of flooding exceeding that of recent days in certain areas of the city, at-risk residents should be ready to evacuate.
So described Greater Sudbury Fire Services Chief Rob Grimwood during a media event at Tom Davies Square on April 21, at which Mayor Paul Lefebvre declared a state of emergency.
“What we’re seeing is not like flooding that has been experienced in recent years,” Grimwood said, later adding that those in flood prone or flooding areas are urged to “to be prepared to leave your property when conditions change.”
Although no forced evacuations have taken place thus far, Grimwood cautioned that city staff are actively preparing for this possibility as part of activating the city’s emergency operations centre on April 18.
“Please stay alert and prepared to act quickly if conditions change,” Grimwood said.
Conservation Sudbury general manager Carl Jorgensen added context to the ongoing flood situation, which started several days ago and slowed down in most areas a few days ago as temperatures cooled and the spring melt abated.
This includes the Belanger/Main Street area of Chelmsford, which was underwater during the weekend and has since receded alongside the Whitson River.
Temperatures are forecast to spike in the coming days, triggering two to three weeks of high-flowing rivers, Jorgensen said.
While the Whitson River system is fairly urban, with a catchment area stretching from Capreol through Chelmsford and south of where there’s currently snowpack, other systems draw from “the bush” up north, where there’s a great deal more snow to melt, Jorgensen said.
There’s approximately 180 mm of water equivalent in snow up to approximately 100 kilometres north of Sudbury which will melt as temperatures increase and flow into the Onaping, Vermillion and Wanapitei watersheds.
It’s these areas which are anticipated to be hit the hardest from what watershed experts can determine at this time, Jorgensen said.
Of particular concern is the lower Vermillion area where various watersheds converge, including at McCharles, Simon and Mud Lakes, at which point the Vermillion River swelling can result in water pushing the wrong way up Junction Creek.
In this same vicinity is the flood-prone Centennial Park and the nearby roads in Whitefish which have already closed due to flooding.
Meanwhile, Jorgensen said Conservation Sudbury said that although Lake Wanapitei is “a huge lake, it’s not limitless in its use as a flood reservoir.”
The Whitson River in Chelmsford and the mid/lower Vermillion River systems have already exceeded a 100-year flood event, Jorgensen said.
For residents in flood areas, the message now is “be prepared to leave if you have not done so already,” Jorgensen said. “Any waterfront properties along those areas are likely to flood if they are not already flooding, and it is very likely that they will be flooding like we have not experienced before.”
Conservation Sudbury will continue to monitor the situation, Jorgensen said, with the most up-to-date information published on their website, available by clicking here. For city watershed maps, click here. Conservation Sudbury's mapping tool to find floodplains is available here.