logo logo

May 5, 2017 – Heavy rainfall event, May 4 to 6, 2017

Heavy rainfall event, May 4 to 6, 2017

Background City of Toronto crews are preparing for rainfall that is expected to continue until through Saturday and add significantly to Toronto’s existing high water levels. The City and agencies including the Toronto and Region Conservation Authority (TRCA) are working with residents to prevent or minimize flooding and related problems. Weather forecast (as of 1 p.m. May 5; source: Environment Canada)

  • Environment Canada is predicting lesser amounts of rainfall for the Toronto area over the next 24 hours, approximately one to two millimetres per hour.
  • While Lake Ontario and watershed levels throughout the city continue to rise, they are doing so at a slower rate.
  • Toronto and Region Conservation Authority (TRCA) continues to monitor and report regularly

  Environmental considerations

  • Current water levels in Lake Ontario as well as rivers and streams throughout the city are still rising, but at a slower rate.
  • The ground remains wet and less able to absorb as much rainfall as quickly as it would under normal spring conditions.
  • During a rain storm, rain will flow on top of the ground and drain into the sewer system. If the ground is oversaturated, ponding may occur.
  • Roadways and other paved surfaces can become flooded quickly and take longer to return to normal conditions.
  • The Toronto and Region Conservation Authority (http://trca.ca/) is monitoring local watersheds for possible flooding.
  • Safety precautions


  • Stay clear of rivers, streams and waterfront areas throughout the city.
  • Use extreme care when travelling through areas where flooding has occurred.
  • Avoid areas known to experience flooding – use alternative routes where possible.
  • Do not drive vehicles into standing water.
  • Use public transit, if possible.
  • During heavy rain storms, avoid travel if possible.
  • Check in on elderly neighbours or other people who may need assistance.
  • Drivers are reminded to use extra caution on the roads, reduce speeds especially near sidewalks where pedestrians are present.
  • All parts of Toronto can be affected by flooding and there may be little or no advance warning that localized flooding is imminent.
  • Information to help residents prepare for extreme weather and weatherproof their homes is available at http://www.toronto.ca/extremeweatherready.

City efforts to reduce flooding impacts

  • City crews are working to keep catch basins clear to minimize the risk of road flooding. (Residents can assist by removing debris from catch basins on local roads in their community.)
  • Crews are monitoring for excessive ponding and flooding and proactively patrolling low-lying areas that have been susceptible to flooding in the past such as the Don Valley Parkway, the Eastern and Western Beaches, areas south of Queen Street, Hoggs Hollow and the Bayview Extension.
  • Residents are asked to call 311 to report any instances of road flooding.

Road conditions

  • Based on information from the Toronto and Region Conservation Authority and Environment Canada, the City has no further plans to close the Don Valley Parkway; should conditions worsen a closure could still be necessary.
  • Water levels in the storm sewer under Lower Simcoe underpass are above the usual catch basin threshold, however there is currently no flooding. Toronto Water has implemented a temporary repair, however temporary flooding could recur. Toronto Water will continue to monitor the underpass.
    • Additionally, the City has recently implemented the first phase of what will eventually be part of a more permanent repair on Lower Simcoe. The work includes modifications to the storm sewer design that leverage the nearby sanitary sewer infrastructure. The City is still in the review and design stage of a more permanent repair that is looking at adding a new storm pump to the existing and nearby Simcoe Pumping

Basement flooding

  • Residents should call 311 immediately to report basement flooding. Toronto Water crews are available 24/7 to respond to flooding calls.
  • Residents should also call Toronto Hydro at 416-542-800 to request a power shut-off to avoid shock or electrocution in the event that water has risen above outlets, near the electrical panel, etc.
  • Clear catch basins and eavestroughs around the home.
  • Consider moving valuables to shelves or upper floors if flooding is imminent. Cleaners, paint or chemicals should be removed from the floor to prevent contamination of floodwater that may enter the home.
  • During an extreme storm, reduce use of water in the home (avoid doing laundry or washing dishes) to prevent water from entering the sewer system, which can become overwhelmed during severe wet-weather events.
  • The City’s sewer system is designed for most storms, however extreme rainstorms can cause sewers to fill faster than the system can manage, resulting in sewer back-ups.
  • o     For example, on July 8, 2013, 126 mm fell between 5 p.m. and 10 p.m.
  • More information about basement flooding, including subsidies available under the City’s Basement Flooding Protection Program, is available at http://www.toronto.ca/basementflood

Update on island and beaches

  • Lake levels continue to rise on the Toronto Islands with localized impacts and ponding.
  • City services and facilities in Toronto Island Park are currently closed or are operating at reduced levels until further notice.
  • The City is taking steps to support Toronto Island residents. Updates and further information are available at http://www.toronto.ca/islands or by calling 311.
  • Five City-managed beaches – Cherry Beach Park, Rouge Beach Park, Woodbine Beach Park, Toronto Island Park and Marie Curtis Park – have already experienced flooding this week. Public access to and use of these areas is restricted.
  • Toronto’s Parks, Forestry and Recreation division is working closely with TRCA to complete remediation work such as bolstering and/or repairing stone break walls and redistributing sand where appropriate to mitigate harmful erosion.
  • Ferry service to Toronto Island Park remains under the following restrictions:
    • Service and access to Toronto Island Park is restricted to required individuals only, such as residents, staff and emergency personnel.
    • Service to Centre Island and Hanlan’s Point docks is cancelled.
    • Service to Ward’s Island dock operates on the spring schedule with no changes.
  • The William Inglis vessel will remain minimally staffed and on-site at the Ward’s Island dock at the end of each day for after-hours storm and temporary shelter, if required.
  • If required, vehicles will be transported to Hanlan’s Island on an as-needed basis.
  • TRCA has issued a warning to members of the public who walk along or up/down the Scarborough Bluffs and waterfront areas – the Bluffs have become saturated with water, making landslides more likely to occur. Signs have been posted in areas where access is temporarily being prohibited.
  • Signs have been posted in areas where access is temporarily being prohibited for your safety

Emergency managemen

  • The City’s Emergency Operations Centre is continuing to monitor the situation and remains prepared to coordinate service responses as needed based on the conditions