Montreal sits in the St. Lawrence River valley in Quebec, where a humid continental climate produces cold, snowy winters and a spring melt season that is one of the region’s biggest annual flood risks.
Built on an island at the confluence of the St. Lawrence and Ottawa rivers, the city closely monitors both waterways during the spring melt season. Ice jams during the spring thaw can cause the St. Lawrence and its tributaries to rise suddenly, and summer convective storms add a second flood risk later in the year, both of which Environment Canada tracks using its national radar network. Learn more: Flash Flood Warning Signs on Radar · Open the full Rain Map