Preparing for severe weather in Ontario

Ontario floods

Flooding in Ontario can happen at any time of the year but is most common in the spring due to rapid snowmelt and rainstorms.

Flooding in Ontario is commonly caused by:

• Rapid snowmelt
• Heavy rain
• Ice jams
• High lake levels or storm surges

How big of a risk are floods in Ontario?

Ontario’s geography and climate make flooding a persistent risk, particularly in low-lying urban areas and near rivers.

Between 2023 and 2024, catastrophic floods caused nearly $1.3 billion in insured losses across Ontario, according to the Insurance Bureau of Canada. The flash floods in Toronto and the GTA in July 2024 were the most destructive, resulting in nearly $1 billion in insured losses.

Toronto also experienced significant damage following floods in 2005 and 2013.

Severe summer storms in Ontario: Rain, hail & tornadoes

Summer weather in Ontario can be volatile. Intense rains and thunderstorms, hail, extreme winds and tornadoes have all caused significant destruction across the province.

Between 2020 and 2023, severe summer weather caused $1.6 billion in insured losses across Ontario. The 2022 derecho — which saw winds hit speeds in excess of 120 km/h — caused more than $875 million in insured damage, according to the Insurance Bureau of Canada.

Ontario wildfires

While wildfires are more common in Western Canada, Ontario experiences significant wildfire activity, particularly in the northern and central regions. Wildfire season in Ontario runs from April to October, with peak activity in July and August.

How big of a risk are wildfires in Ontario?

Ontario has vast forested regions that are vulnerable to wildfires, particularly in dry and hot conditions. In the past 10 years, Ontario has averaged nearly 700 wildfires each season.