Conservation officials in Chatham-Kent are warning that heavy rain beginning overnight Thursday could cause ponding and localized flooding.
The Lower Thames Valley Conservation Authority (LTVCA) also said local watercourses will rise and some could spill their banks.
A total of 15 to 25 mm of rain is predicted until Thursday afternoon.
Accumulated ice and snow in the watercourses could block drainage leading to even higher water levels, said the LTVCA.
If the higher rainfall amounts appear, it is possible that McGregor Creek in Chatham could rise enough that the LTVCA would have to operate the McGregor Creek Diversion Channel and is prepared to do so if necessary.
Temperatures will remain above freezing during the rain event and the LTVCA said the ice still on the Thames River and in local watercourses has been significantly weakened by the warm temperatures and will be further weakened with the rain in the forecast.
The Conservation Authority is asking people to be careful and avoid the river, ditches, and streams because the combination of slippery banks and fast-moving cold water can be dangerous.
The LTVCA also said there's a risk of flooding along Erie Shore Drive in Chatham-Kent because of a Gale Warning in effect for Lake Erie. The Conservation Authority said there's also a risk of shoreline damage and erosion all along the Lake Erie shoreline, including the high bluffs due to strong winds Thursday afternoon into the overnight.
The forecasts for the open lake suggest waves could reach two to three metres Thursday evening.
