GRCA Flood Message #6 – Combined Flood Warning and Flood Watch

The Grand River Conservation Authority (GRCA) is issuing Flood Warning messages for the City of Cambridge and Six Nations and upgrading the Flood Warning message for West Montrose.

Previous Flood Warning messages and the Flood Watch message for the remainder of the Grand River watershed remain in effect.

Weather forecast

Warm weather and rain over the past 4 days have melted the snowpack and have led to ice jams and flooding. While the risk of ice jams is believed to be past, river flows remain extremely high. Environment Canada has issued a Special Weather Statement covering all of southern Ontario including the Grand River watershed with rainfall amounts between 20 and 40 mm beginning Tuesday, March 10 and into Wednesday. Thunderstorms may result in locally higher rainfall amounts. River levels are elevated and additional runoff from rainfall will cause river flows to increase further.

Additional Flood Warnings Being Issued

The GRCA is issuing Flood Warning messages for the City of Cambridge and Six Nations and upgrading the Flood Warning message for West Montrose.

Flood Warning (Action) Message for City of Cambridge

River flows are expected to increase in the lower Speed River in the late morning Tuesday, March 10, and will remain elevated resulting in flooding of low-lying areas. Municipal flood coordinators in the City of Cambridge have been advised to notify affected properties and monitor conditions.

Flood Warning (Action) Message for Six Nations

River flows are high and are expected to increase in the lower Grand River throughout Tuesday, March 10, and will result in flooding of low-lying areas. Municipal flood coordinators in Six Nations have been advised to notify affected properties and monitor conditions.

Flood Warning (Action) Message for West Montrose

River flows are expected to reach Flood Warning Zone 3 in West Montrose midday Tuesday, March 10. Municipal flood coordinators in the Township of Woolwich have been advised to notify affected properties and monitor conditions. Residents are encouraged to refer to the guide on the GRCA’s website for information regarding flood warning zones.

Previously Issued Flood Warnings and Flood Watch Remain in Effect

Flood Warning messages for Grand Valley, St. Jacobs, Village of Conestogo, New Hamburg, Ayr, Drayton, Brant County, Brantford and Haldimand County and the Flood Watch message for the remainder of the Grand River watershed remain in effect.

Flood Warning (Action) Message for Grand Valley

River flows have exceeded flood thresholds in Grand Valley and will continue to affect this area. The flood risk remains high due to the forecast rainfall. Municipal flood coordinators in Grand Valley have been advised to monitor conditions and take necessary actions.

Flood Warning (Action) Message for St. Jacobs

River flows have resulted in flooding of low-lying areas in St. Jacobs and will continue to affect this area. The flood risk remains high due to the forecast rainfall. Municipal flood coordinators in the Township of Woolwich have been advised to monitor conditions.

Flood Warning (Action) Message for Village of Conestogo

River flows in the Grand and Conestogo Rivers are expected to increase midday Tuesday, March 10, and will result in flooding of low-lying areas. The flood risk remains high due to the forecast rainfall. Municipal flood coordinators in the Township of Woolwich have been advised to notify affected properties and monitor conditions.

Flood Warning (Action) Message for New Hamburg

River flows peaked in Flood Warning Zone 2 in New Hamburg and have declined. However, the flood risk remains high due to the forecast rainfall. Municipal flood coordinators in the Township of Wilmot have been advised to notify affected properties and monitor conditions. Residents are encouraged to refer to the guide on the GRCA’s website for information regarding flood warning zones.

Flood Warning (Action) Message for Ayr

River flows are in Flood Warning Zone 1. The flood risk remains high due to the forecast rainfall. Municipal flood coordinators in the Township of North Dumfries have been advised to notify affected properties and monitor conditions. Residents are encouraged to refer to the guide on the GRCA’s website for information regarding flood warning zones.

Flood Warning (Action) Message for Drayton

River flows peaked in Flood Warning Zone 1 in Drayton and the flood risk remains high due to the forecast rainfall. Municipal flood coordinators in Mapleton Township have been advised to monitor conditions. Residents are encouraged to refer to the guide on the GRCA’s website for information regarding flood warning zones.

Flood Warning (Action) Message for Brant County

River flows have reached Flood Warning Zone 2 on the Grand River from Glen Morris to Paris (Penman's Dam) and will remain elevated.

River flows have reached Flood Warning Zone 3 on the Grand River from Paris (Penman's Dam) to Onondaga and will remain elevated.

River flows have reached Flood Warning Zone 2 on the Nith River in Paris and are expected to remain elevated.

The flood risk remains high due to the forecast rainfall. Municipal flood coordinators in the County of Brant have been advised to notify affected properties and monitor conditions. Residents are encouraged to refer to the Flooding section of the County of Brant website for information regarding flood warning zones.

Flood Warning (Action) Message for Brantford

River flows have reached Flood Warning Zone 3 on the Grand River in Brantford. The flood risk remains high due to the forecast rainfall. Municipal flood coordinators in the City of Brantford have been advised to monitor conditions. Residents are encouraged to refer to the Flood Preparedness section of the City of Brantford’s website for information regarding flood warning zones.

Flood Warning (Action) Message for Haldimand County

River flows have continued to increase and are expected to peak in York on Tuesday, March 10, resulting in flooding of low-lying areas. The flood risk remains high due to the forecast rainfall. Municipal flood coordinators in Haldimand County have been advised to notify affected properties and monitor conditions.

Flood Watch remains in effect for the remainder of the Grand River watershed

Most of the snowpack across the watershed has melted from recent warm temperatures, which has continued to increase water levels in rivers, streams and reservoirs. Forecast rainfall is expected to further increase water levels throughout the watershed. Higher flows in local waterways combined with additional runoff from this event is increasing the risk of flooding. Municipal flood coordinators should monitor areas where flooding is known to occur.

GRCA Reservoirs

The major reservoirs at Belwood, Conestogo, Guelph, Luther, Woolwich, Laurel, and Shade’s are being used to help reduce the impact of downstream flooding.

Stay safe 

High flows and unstable ice conditions will increase the safety risk around rivers and streams throughout the watershed. The public is encouraged to exercise extreme caution around local waterways. Parents are reminded to keep their children and pets away from watercourses. The public is reminded to stay off ice-covered waterbodies, due to unsafe conditions.

River conditions and forecasts are being monitored closely, and any additional flood messages will be issued as needed.

This message will remain in effect until 12 p.m. on Thursday, March 12, 2026. 

More information

• For more information on flows, weather and reservoir conditions see the River Data section of the GRCA website.
• More information on the flood warning system is available on the GRCA website.
• Receive GRCA flood messages by e-mail by subscribing through the GRCA website.
• Follow GRCA flood messages on X at grca_flood_msg.
• More information about how the GRCA’s role in managing floods is available in the Flooding section of the website.
• Copies of the GRCA’s River Safety Rules booklet is available by contacting the GRCA Administration Centre

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Media contacts:

Lisa Stocco, GRCA Director of Strategic Communications and Environmental Education
Phone 519-621-2763 x2316 | Email lstocco@grandriver.ca

Serena Catania, GRCA Supervisor of Communications and Marketing
Phone 519-621-2763 x2240 | Email scatania@grandriver.ca