The Thames Valley Conservation Authority and the municipality of Chatham-Kent are warning that thunderstorms predicted for today will bring large amounts of water that pose a risk of flooding.
Total rainfall amounts of 25 to 50 mm are expected, with the highest amounts forecast to be in the Windsor-Sarnia to Hamilton-Niagara corridor. In addition, thunderstorms will be possible over southwestern Ontario and the Golden Horseshoe, and might result in locally higher rainfall amounts. Significant snow melt due to the rising temperatures is a concern. As the rain comes to an end from west to east Friday, winds will increase out of the southwest with gusts to 70 or 80 km/h possible, particularly along the great lake shores.
The snowpack in the lower watershed has 50 to 70 mm of water equivalent, while the upper watershed has over 85 mm. The rainfall and warm temperatures are expected to melt a good portion of the snowpack.
The Thames River will rise and flood the river flats from Delaware to Chatham. This could occur by late Friday due to our local runoff and be sustained into early next week as water from the upper Thames moves through the system. People undertaking agricultural activities in the river flats should be advised of these conditions. There is some risk of ice jam formation as there is sufficient ice thickness on the Thames River, however, it is yet to been seen if the flows in the river will be sufficient for ice jam formation.
Localized flooding is likely to occur on the region’s smaller watercourses. The accumulation of snow and ice will make it difficult for the water to drain off the landscape. Localized flooding is also possible in urban areas. The Conservation Authority is preparing to use the diversion channel if required.
Alan DeVillaer, coordinator of Emergency Medical Services and emergency management for the municipality of Chatham-Kent advises residents to be aware of flood conditions. They are advised to keep storm drain grates clear on their streets, remove items from their basements, and check their sump pumps.
DeVillaer says that people should take extra caution and avoid the river, lakes, ditches, streams, and ponds. Ice conditions are expected to degrade. A combination of slippery banks, moving/melting ice and cold water is particularly dangerous. Parents should pay special attention to keep their children away from the water.