Flood Potential: High
The Ganaraska Region Conservation Authority advises that the water level of Lake Ontario is currently at 75.35 m above sea level (as measured at Cobourg) which is 40 cm above normal and 57 cm below the record high set in 2019. While water levels are expected to continue to gradually rise for the next few weeks as spring runoff and above average inflows from Lake Erie continue, Lake Ontario is forecast to peak well below the record highs of 2017 and 2019.
An approaching low pressure system is forecast to bring 30 to 50 mm of rain over a two day period beginning Wednesday morning. While no immediate flooding is anticipated as a result of the rain, high flows in ditches and streams are expected. Strong winds are also expected with gusts reaching 65 km/h from the East on Wednesday and up to 50 km/h from the Southeast on Thursday, which could result in wave action and uprush along the Lake Ontario shoreline. Coastal wetlands may become backwatered and flooding of low lying shorelines is possible as a result.
Residents are reminded to stay well clear of shorelines during strong onshore winds when wave action may be actively eroding the shoreline creating hazardous conditions.
This message applies to the Lake Ontario shoreline and coastal wetlands only. The forecasted rainfall will cause an increase in local stream levels and flows, however no flooding is anticipated.
This Flood Watch for the shoreline of Lake Ontario within the Ganaraska region will be in effect through Sunday, May 31st, 2020. Conservation Authority staff will continue to monitor conditions, and provide updates as necessary. Should you have any questions or wish to report flooding, please contact the following GRCA staff at 905-885-8173.
Mike Smith Cory Harris, P.Eng.
Flood Operations Officer Flood Warning Coordinator
Note: A Flood Watch is issued as notice that flooding is possible in specific watercourses or municipalities. Municipalities, emergency services and individual landowners in flood-prone areas should prepare.