The Ausable Bayfield Conservation Authority (ABCA) has issued a Flood Outlook and Water Safety message for the region.
It said an approaching warm front will be followed by rainfall of up to 10 millimetres over the next 36 hours.
The ABCA said the rain, which started Monday, and temperatures remaining above freezing over the next several days will melt most of the snowpack.
The authority said areas with less snow accumulated may still experience high flows and flooding, to low-lying areas, due to flows associated with snowmelt from upstream.
Based on the current weather predictions, river-flow forecast models indicate that levels in watercourses will quickly rise beginning Monday evening, peaking on Tuesday, and Wednesday.
The ABCA said while many watercourses are expected to exceed their banks, major flooding is not anticipated at this time, with flooded areas limited to the low-lying undeveloped flood plains.
The potential extent of flooding will depend on the actual temperatures and rainfall.
Municipal staff are asked to monitor local drainage problem areas where snow conditions may have covered catch basins.
The message will remain in effect until 9 a.m. on Thursday.