Flood Forecasting and Warning Program

Information about the Flood Forecasting and Warning Program, which prepares provincial and local authorities in the event of a flood.

Special Lake Ontario Flood Watch

Special Lake Ontario Flood Watch Issued By Ministry of Natural Resources' Surface Water Monitoring Centre for May 31st, 2017

Current flood information

Flood information updated as of: July 20, 2017 - 10:30 am

Ontario flood map

Provincial Watershed Conditions Statement for Southern Ontario issued by Surface Water Monitoring Centre of the Ministry of Natural Resources and Forestry Wednesday July 19, 2017 at 10:30 AM

Locally issued flood messages

Issued by MNRF Districts and Conservation Authorities

MNRF Districts


    Conservation Authorities

    • Cataraqui Region - Flood Warning Extended For Lake Ontario & St. Lawrence River - June 29, 2017
    • Central Lake Ontario - Flood Warning Update - Lake Ontario Shoreline - June 29, 2017
    • Credit Valley - Lake Ontario Flood Watch - Message #3 - July 14, 2017 4:00 pm
    • Crowe Valley - Watershed Conditions Statement – Water Safety - July 5, 2017 10:00 am
    • Ganaraska Region - Flood Watch - Lake Ontario - June 20, 2017
    • Hamilton - Watershed Conditions Statement: - July 18, 2017
    • Lower Trent - Flood Warning Update for Lake Ontario/Bay of Quinte - July 14, 2017 2:00 pm
    • Mississippi Valley - Flood Watch for Little Marble Lake and Dalhousie Lake - July 19, 2017 4:00 pm
    • Quinte - Flood Warning For Bay Of Quinte and Lake Ontario Shorelines in the Quinte Conservation Watersheds - June 28, 2017
    • Rideau Valley - Rain Causing Higher Water Levels in Rideau River Watershed - July 14, 2017 12:30 pm
    • South Nation - Flood Watch St. Lawrence - Update #7 - June 22, 2017
    • Toronto and Region - Watershed Conditions Statement – Lake Ontario - May 9, 2017

    River Regulatory Agencies

    Provincial Message

    Issued to Local Authorities by the Surface Water Monitoring Centre


    MNRF Districts

    Aurora, Aylmer, Guelph, Midhurst, Parry Sound

    Conservation Authorities

    Ausable Bayfield, Catfish Creek, Credit Valley, Essex Region, Ganaraska Region, Grand River, Grey Sauble, Halton, Hamilton, Kettle Creek, Lake Simcoe Region, Long Point Region, Lower Thames Valley, Maitland Valley, Niagara Peninsula, Nottawasaga Valley, Saugeen, St. Clair Region, Toronto and Region, Upper Thames River

    Weather Situation

    A mesoscale convective system that is currently developing and active in the Michigan Wisconsin area today is likely to track into the southwest of the province Thursday. The path and intensity of this system is still uncertain. The passage of this system in the southwest of the province could result in widespread heavy downpours accompanied by thunderstorms on Thursday with rainfall amounts totalling 25 to 50 mm or more locally. At the current time areas to the west of line from Toronto to Barrie are at risk of this active weather. For the weekend there is further rain forecast to this region due to the passage of yet another low pressure system in the area.

    High winds are likely Thursday due to the passage of the mesoscale convective system in the Lower Great Lakes Region. Generally 20 to 35 km/h winds from west/southwest are forecast at this time.


    NOTE: Lake Ontario and Lake Erie levels continue to be elevated and are forecast to remain so for all of the month of July. See our Special Lake Ontario Flood Watch for more information at www.ontario.ca/flooding.

    Streamflow and levels are seasonal for this time of the year in most of region. However due to recent rainfall and active weather in the region soils have reduced capacity to store water and can produce runoff more readily resulting in high water and flooding conditions locally. Short and intense storms, such as the one associated with this weather system has the potential to cause increased runoff and result in localised flooding anywhere in the forecast region.

    Winds from west - southwest in the 20 to 35 km/h range in the Lower Great Lakes Region have the potential to cause high waves and storm surge that could result in shoreline flooding or worsening existing conditions.

    Close attention should be paid to local flood conditions reports from conservation authorities and municipalities, and as always, a close watch on meteorological conditions, including thunderstorm alerts, is recommended.

    This message will be in effect until (or updated before) Saturday July 22, 2017 at 5 PM.

    Flood Message Definitions

    Provincial flood messages

    There are 2 types of provincial flood messages:

    • the Provincial Flood Watch, which provides consistent and timely technical information about the potential for flooding
    • the Provincial Watershed Conditions Statement, which provides information on provincial watershed conditions as they relate to flood potential, and an outlook on expected spring flood conditions

    Local flood messages

    There are 3 types of local flood messages:

    • flood warning: flooding is imminent or already occurring
    • flood watch: there is the potential for flooding
    • watershed conditions statements: flood Outlook (an early notice of the potential for flooding based on heavy rain, snow melt etc.) and water safety information.

    Who to contact for flood information

    Your local Conservation Authority is responsible for local flood messaging.

    Your local municipality is responsible for on-the-ground flood response.

    If you live in a community that is not serviced by a conservation authority, any flood watches or flood warnings in your area are issued by the nearest Ministry of Natural Resources and Forestry district office.


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    Updated: August 19, 2016