TRCA’s Flood Forecasting and Warning Program is Here to Help Prepare You for Flooding

TRCA Monitors Risk and Hazards

The Greater Toronto Area grants access to many rivers, lakes and streams. The proximity to these bodies of water, and the natural floodplains alongside them pose a possible hazard and risk for flooding.

TRCA team members view impact of spring flooding event on Toronto Islands

Toronto and Region Conservation Authority (TRCA) provides environmental protection and hazard management to mitigate the risk of flooding and erosion.

Specifically, TRCA identifies and maps flood hazards to reduce flood risk, operates flood mitigation infrastructure, and provides flood forecasting and warning services through the mandated Flood Forecasting and Warning (FFW) program.

What is the FFW Program and Why is it Important?

The Flood Forecasting and Warning (FFW) program was designed to reduce the risk to life and damage to property caused by flooding. The program provides local municipalities and the public with flood messages that notify, inform, and advise so they can respond during severe rainfall events and flood-related emergencies.

TRCA’s FFW program staff are responsible for assessing and monitoring conditions that could cause floods. Flood staff monitor weather and watershed conditions, issue flood warning messages, operate flood control infrastructure, advise TRCA’s municipal partners on flood risk and maintain communications with agencies during storm events.

Palgrave Dam

TRCA acts in an advisory capacity during flood events by providing valuable flood risk information and technical support to municipalities, who are ultimately responsible for activating municipal emergency response procedures and actions, including evacuations and road closures.

How Does TRCA Provide Flood Warnings? By Issuing Flood Messages

If heavy rainfall (also known as “precipitation”) causes water levels and stream flow in rivers to rise, flooding could occur in the adjacent floodplain areas.

TRCA issues a flood message for its entire jurisdiction when flooding is possible or about to occur. The message is posted on website and emailed to municipalities, school boards, the media, and members of the public who have signed up to receive the messages.

Sign up to get flood message emails from TRCA

In addition to issuing flood messages, there are many other activities taking place during flood events. TRCA dam operators carry out gate operations if necessary, and hydrometric staff maintain TRCA’s network of rain and stream gauges.

During floods, TRCA flood staff may also conduct site visits to investigate and document river conditions.

TRCA flood duty officer

Tools used to Monitor for Flooding in TRCA’s Jurisdiction

One of the tools used to monitor watersheds as part of the FFW program includes TRCA’s newly enhanced flood monitoring website,

This website was designed as a resource to help TRCA flood duty staff assess current watershed and weather conditions in TRCA’s jurisdiction by providing access to real-time precipitation and water level measurements.

screenshot of TRCA gauging website

The website is publicly available and offers data and information on current conditions to the public. For example, residents can see how much rain has fallen in one area or how much the water level has risen in a certain river.

The Flood Monitoring Website can serve as an awareness tool for residents to know the conditions in their local rivers and be better informed on conditions. TRCA’s flood messages will also be displayed on the flood monitoring website if an active flood message is in effect.

Features of the Flood Monitoring Website that Help You Stay Informed

The station map uses shapes, colours, and symbols to quickly assess the flood risk conditions in TRCA’s watersheds.

The TRCA real-time gauging map uses shapes colours and symbols to quickly assess the flood risk conditions

Other features include:

Homepage and Station Map


Gauge Page




Downloads and Reports


About TRCA’s Real-Time Monitoring Equipment

TRCA uses stream and precipitation gauges which transmit recorded measurements back to staff in near real-time. These gauges are connected to a database through a cellular internet connection and then displayed on the website.

Learn more about TRCA’s Real-Time Flood Monitoring Network.

three-season tipping bucket gauge
four-season gauge
stream gauge hut

Examples of precipitation gauges (above left and centre) and a stream gauge (above right).

Where: At TRCAGauging.CA

To start exploring conditions at your local river or stream now, visit

Download a copy of TRCA’s Flood Monitoring Website Guide to learn more.

Discover more information on riverine flooding and use the resources compiled at to stay well-informed of the latest flood-related information.