The Grand River Conservation Authority (GRCA) is responsible for forecasting floods and issuing flood warnings.
- Watershed conditions statement: Issued when river and channel conditions exist. There are two categories of statements:
- Water Safety: High flows, unsafe banks, melting ice or other factors have made watercourses dangerous for recreational users e.g. canoeists, swimmers, anglers, hikers, boaters, etc. but flooding is not expected.
- Flood Outlook: Early notice of the potential for flooding based on weather forecasts calling for heavy rain, snow melt, high winds or other conditions that could result in high runoff or ice jams or lakeshore flooding.
- Flood Watch: Flooding is possible. Municipalities and individuals should prepare.
- Flood Warning: Flooding is occurring or is about to occur. Municipalities and individuals should take action to deal with flood conditions. This may include road closures and evacuations. The warning may include forecasts of how high the water will rise and the time of the peak.
When flooding is possible or occurring, messages are sent to municipal flood coordinators, police services, radio stations and televisions stations throughout the watershed.
Municipal flood co-ordinators are senior municipal staff, such as fire chiefs and public works managers, who are familiar with flooding conditions in their community and can mobilize staff and resources to implement the local flood response plan.