Highlights:

• Special Weather Statement in effect
• Various forecasts calling for 10 to 35 mm of rain Wednesday evening into Thursday afternoon.
• Ponding and localized flooding is possible
• Higher rainfall amounts would cause local watercourses to rise and some could spill their banks.
• Higher rainfall amounts could also cause breakup and movement of ice on the Thames River.

Message:

There is currently a Special Weather Statement in effect from Environment and Climate Change Canada calling for a “messy mix of wintery weather beginning late Wednesday”. This includes 10 to 25 mm of rain from late Wednesday through Thursday afternoon. Other forecasts are suggesting there could be up to 35 mm of rain. Temperatures are predicted to rise above freezing Wednesday morning and with rain arriving in the evening. Rain is then predicted to last into Thursday afternoon when temperatures are predicted to fall back below freezing with the rain changing to freezing rain or snow. Forecasts note that the track of the low pressure system predicted to bring this weather is still uncertain and the timing, types of precipitation and total amounts could change.

The warm temperatures and rain will melt out most of the remaining snow in the west of the lower Thames watershed. The higher rainfall amounts are likely to do the same in the east of the lower Thames watershed. Given the frozen ground conditions, this amount of rain forecast will likely cause ponding, standing water and localized flooding in low lying areas and areas of poor drainage. Smaller local watercourses will rise and some could spill their banks. Many of these smaller local watercourses are still filled with snow and ice which could cause blockages and add to drainage issues. With the amount of rain in the forecasts, the LTVCA is prepared to have to operate the McGregor Creek Diversion Channel.

The higher rainfall amounts predicted could also produce flows in the river high enough to flood the low lying river flats adjacent to the river from Delaware down to Chatham.

Given the amount of rain in the forecast, it is possible that the Thames River will rise up enough to cause the river ice to break up and begin moving. Once the warm up begins, the ice on the river should no longer be considered safe. Ice cover on the river through Chatham and downstream to the mouth is around 20 cm thick. This amount of ice is roughly the same amount of ice that allowed for ice jams in 2011 and 2019. If the ice begins to break up, the river will need to be watched closely for the possibility of ice jams.

People should take extra caution and avoid the river, ditches, and streams. The combination of slippery banks, broken or unstable ice and fast moving cold water can be dangerous. Standing water can also present its own unseen hazards. Children and pets and livestock should be kept away from the water.

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

This message will be in effect until February 18th, 2022.

Message Contact: Jason Wintermute ([email protected])