Highlights:

• Risk of shoreline erosion and damage to shoreline protection along the north shore of Lake Erie Thursday morning and overnight into Friday.
• Risk of flooding on Erie Shore Drive Thursday morning through to Friday.
• Rain in the forecast could aggravate flooding in low-lying shoreline communities such as Shrewsbury near the outlet of watercourses and municipal drains.
• Rain in the forecast could result in localized flooding along municipal drains and watercourses.
• There is the potential that the Indian-McGregor Creek Diversion Channel will be utilized in diverting floodwaters around the City of Chatham.

Message:

Strong winds out of the southeast, south, and southwest are currently forecasted for Thursday morning into early Friday. Current forecasts suggest that the winds will pick up and could exceed 35 km/hour early Thursday morning and continue to be high until early Friday morning. Sustained winds out of the south are currently forecasted to peak at 45 km/hour with gusts up to 65 km/hour Thursday evening. Wave forecasts are generally calling for waves on Lake Erie to build to two metres in height Thursday.

There is a risk that wave action could damage shoreline protection works and cause erosion all along the Lake Erie shoreline in Chatham-Kent and Elgin County, including along the high bluff areas. Flooding could also occur in low-lying, south facing shoreline areas such as along Erie Shore Drive in Chatham-Kent. While the southeast and southwest wind directions tend to be along-shore on Lake Erie and rarely produces significant flooding, the current forecast is calling for the wind to be out of the south for most of Thursday. Generally, the worst flooding on Erie Shore Drive is when the winds are directly out of the south. The prolonged period of high winds out of the south could also have a greater impact than expected. Residents should pay attention to local conditions and be prepared.

People should take extra caution and avoid the shoreline should conditions get rough. The waves can be strong and the shoreline slippery. There could also be hazardous debris within the waves and water which could be thrown onto the shore. Standing water can also present unseen hazards. Children and animals should be kept away from the water.

In Chatham-Kent, weather forecasts are currently predicting up to 70 mm of rainfall starting late Thursday evening and ending late on Saturday. The majority of the forecasted rainfall is supposed to arrive on Saturday. If those volumes are realized and distributed over a short time period and given local ground conditions, there is a chance that the LTVCA may have to close the Rivard Dam and divert floodwaters from the McGregor Creek watershed around the City of Chatham. LTVCA staff will be monitoring the situation and act according to how it plays out.

The rain in the forecast for Thursday, Friday, and Saturday could aggravate the flooding situation along the shoreline. The water level (and groundwater table) is so high in shoreline areas that the rain will have problems draining away and may lead to localized flooding. In addition, those watercourses that drain into the lakes are already very high in their downstream ends due to high lake levels. The additional rain has the potential to cause excess flooding from these watercourses. Shrewsbury would be a community particularly at risk from this, although other areas could be impacted too.

Higher volumes of rainfall are currently forecast for the upper Thames River watershed east of Chatham-Kent (up to 95 mm). If those volumes are realized over a short time span, flooding along the Thames River flats may be observed heading into next week. Drains and creeks may top their banks and flood adjacent lands and flood flats during the event.

The public 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 12 January 2020.