Highlights:

• Rainfall amounts of 20 to 35 mm predicted over the next 48 hours.
• Potential thunderstorms could drop more in some areas.
• Local watercourses will rise and some could reach bank full conditions or spill their banks.
• LTVCA may need to operate the McGregor Creek Diversion Channel.
• High lake levels could aggravate drainage issues in shoreline areas.
• Thames River should be expected to rise up enough to flood the sidewalk in downtown Chatham.

Message:

Forecasts are calling for a significant rainfall event to begin this evening and to last through Sunday morning. Total rainfall predicted for this event ranges from 20 to 35 mm with the potential for thunderstorms to drop additional precipitation in some areas. The ground is still wet from rain over the last few days and has less ability to absorb this new rain.

The amount of rain in the forecast is significant for this time of the year. The amount of rain could be expected to cause ponding and localized flooding in areas with poor drainage. Local ditches, creeks and streams should be expected to being rising late tomorrow morning or afternoon and some could reach bank full conditions or spill their banks. If we get the upper end of the rainfall predictions, the LTVCA would expect to have to operate McGregor Creek Diversion Channel to protect the south end of the city of Chatham from flooding.

The rain in the forecast could have a greater impact in shoreline areas. Due to the high lake levels, rainwater is not draining properly from these areas. In addition, any water from upstream making its way downstream on local watercourses into these shoreline areas could further impact these areas.

The high water levels on Lake St. Clair are having an impact on water levels in the Thames River all the way up into the city of Chatham. Water levels on the river should be expected to rise and flood the sidewalk along the river in downtown Chatham. Significant flooding beyond this is not expected.

In order to reduce nuisance flooding, residents should ensure that catch basins and other drainage areas are clear of debris.

People should take extra caution and avoid the river, ditches, and streams. The combination of slippery banks and fast moving cold water can be dangerous. Standing water can also present unseen hazards. Children and animals should be kept away from the water.

Officials will continue to monitor the situation and update this advisory if necessary.

This message will be in effect until March 30, 2020.

Message Contact: Jason Wintermute (jason.wintermute@ltvca.ca)