The Maitland Valley Conservation Authority has issued a Flood Watch for all municipalities in the Maitland and Nine Mile River watersheds.
A Flood Watch means that flooding is possible but not imminent or certain.
A Colorado Low will track through Southern Ontario today, bringing warm temperatures and widespread rainfall totals of 20-40 mm, with locally higher amounts possible in the southern portions of the watershed. Temperatures are forecast to rise above freezing this afternoon and continue to increase, reaching a high near 7℃. Temperatures will then fall below freezing early Monday morning as precipitation transitions to snow.
Snowmelt combined with rainfall and frozen ground conditions will intensify runoff and may result in a rapid and strong river level response. The degree of snowmelt and runoff will remain highly uncertain due to near frozen ground conditions and the amount of rainfall that materializes, leading to a wide range of possible outcomes – from typical flooding in low-lying and flood-prone areas to more extensive flooding in some locations. Water levels are expected to rise quickly overnight, with peak flows anticipated Monday afternoon. Elevated and cresting flows may persist into Wednesday for downstream portions of the watershed. Flooding may be worsened by restricted drainage caused by snow and ice.
Municipal officials are encouraged to check and maintain drainage systems and monitor low-lying and flood prone roads. The public is reminded that slippery and unstable streambanks, combined with fast-moving cold water, will create hazardous conditions near all watercourses.
Maitland Conservation will continue to monitor conditions and will provide updates as required.
This message is in effect until the afternoon of Tuesday December 30, 2025.
Contact:
Jeff Winzenried, Flood Forecasting Supervisor
jwinzenried@mvca.on.ca
Types of Flood Messages:
Watershed Conditions Statement – Water Safety – General watershed conditions are being assessed for high runoff potential that could lead to flooding, and to remind the public of general river safety issues.
Watershed Conditions Statement – Flood Outlook – Early notice of the potential for flooding based on weather forecasts calling for heavy rain, snow melt, high wind or other conditions that could lead to high runoff, cause ice jams, lakeshore flooding or erosion.
Flood Watch – Flooding is possible in specific watercourses or municipalities. Municipalities, emergency services and individual landowners in flood-prone areas should prepare.
Flood Warning – Flooding is imminent or already occurring in specific watercourses or municipalities. Municipalities and individuals should take action to deal with flood conditions. This may include road closures and evacuations.