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CLOCA issues flood warning

Posted on Friday June 14, 2019

Flood Warning - Lake Ontario Shoreline- Update 2


Subject:       Notice of Severe Imminent Flood Conditions- Update 2

The Central Lake Ontario Conservation Authority advises that the previously issued Lake Ontario Shoreline Flood Warning has been updated to reflect current conditions.

Small amounts of precipitation are forecast across the region for the next 5 days (June 15- 19). However, forecast winds over the Lower Great Lakes may reach or exceed 30 km/hr with sustained gusts exceeding 50 km/hr. Of particular concern are the winds coming out of the south projected for today and the weekend, which will drive towards the north shore of Lake Ontario. The above average water levels combined with significant winds are likely to result in the localized flooding of nearshore properties, low-lying and flood prone areas due to storm surge and wave uprush. 

Water levels in all of the Great Lakes are well above seasonal average, with Lake Erie and Lake Ontario having recorded new historically high levels. As a result, inflow to Lake Ontario from Lake Erie via the Niagara River will continue to be above average for the spring and summer. Areas downstream of Lake Ontario in the St Lawrence River have been experiencing major flooding with record flow contributions from the Ottawa River near Montreal. Lake Ontario outflow is regulated at the Moses Saunders dam near Cornwall and follows an approved plan. Current outflow rates are set to balance high Lake Ontario water levels and St Lawrence River flooding conditions.

More information on Lake Ontario water levels and regulation can be found here:

CLOCA monitors water levels and weather forecasts and issues flood messages for our portion of the Lake Ontario shoreline when either of the following criteria are met:

  1. Static water level equal to or greater than 75.5 m
  2. Static water level equal to or greater than 75.1 m AND projected (offshore) wave heights of 2.0m or greater.

The Lake Ontario water level reported in the most recent briefing (June 13, 2019) from the ILOSRB is 75.91 m, having dropped slightly from the historic high, and staying at the same overall level for the previous seven days. Lake Ontario outflows are now at levels equivalent to the record high outflows released in the summer of 2017. However, with predicted strong winds, residents and property owners in locations susceptible to shoreline flooding should make preparations for flooding.

Information on flood preparedness can be found here:

Residents are advised to avoid and/or exercise caution around all Lake Ontario shoreline areas. Elevated water levels, waves, and eroded bluffs and shorelines all pose safety concerns. Use extra caution, stay away from any areas experiencing erosion or any areas that are flooded, and alert any children under your care of these dangers and supervise their activities.

While Lake Ontario’s water level is expected to slowly decline over the coming weeks, levels will continue to be above flood watch levels through the month of July. Due to continuing high lake levels and the potential for wind driven storm surge, this Flood Warning will be in effect through to Friday July 19, 2019. The Central Lake Ontario Conservation Authority will continue to monitor the conditions and will provide updates as required.

To report flooding or for further information, please contact the flood duty officer at (905) 579-0411 ext 134.

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