Intense Rainfall for Toronto

16th July, 2024. Environment Canada confirm over 4 inches, (100mm) fell in the City in about 2.5 hours during the morning of Tuesday 16th, making it the 5th wettest day at Pearson Airport. Intensities of 30mm in 30 minutes were observed in the city, caused by training thunderstorms. This followed storms on the afternoon of 15th. The Don Valley area saw the greatest impact, largely related to road flooding. The Don Valley had a significant population living close to the watercourse until Hurricane Hazel in 1954, after which the homes were expropriated and land used for an expressway and parkland.