Ausable Bayfield Conservation is warning of high water flows in streams due to heavy rain in the forecast.
The relatively mild temperatures, and melting of most of the snowpack recently, has lead to above seasonal flows.
Tonight's forecast of 20 - 30 mm of heavy rain on saturated or frozen ground could result in fast rising water in streams and rivers.
Levels could approach or exceed bank-full conditions, and lead to localized flooding in traditional low lying flood plains.
Residents should avoid all watercourses, which are extremely cold, fast running, with slippery unstable banks.