Back-to-back historic storm events, described as 1-in-100 year and 1-in-50 year, hit Halton in mid-July, triggering localized flash floods and causing basement flooding in nearly 2,000 homes.
Here’s a closer look at the impact by the numbers, as shared by the Region.
- Between July 10 and 14, Halton sustained significant low-intensity rainfall, causing wastewater system flows to run at two to five times higher than the normal rate.
- On July 15, a 1-in-100-year storm event delivered 74 mm of rainfall in Burlington and 60 mm in Oakville.
- On July 16, a 1-in-50-year storm event brought up to 79 mm of rainfall in Halton Hills, 70 mm in Milton and 52 mm in Oakville.
- In total, Halton received 100 to 220 mm of rainfall over the week, equivalent to 25 per cent of the region’s average annual rainfall.
Over the following six weeks, Halton Region responded to 4,400 flood-related calls and assessed 1,897 homes reporting basement flooding.
- Burlington: 1,620 reports, with 46 per cent of properties flooded directly by storm water and 54 per cent due to stormwater-induced wastewater system surcharges.
- Halton Hills: 124 reports, with 22 per cent from direct stormwater flooding and 78 per cent from surcharged wastewater systems.
- Oakville: 104 reports, with 49 per cent due to stormwater and 51 per cent from surcharged wastewater systems.
- Milton: 49 reports, with 55 per cent from stormwater and 45 per cent from wastewater surcharges.
Halton Region received 929 grant applicants from homeowners impacted by the flooding. The $1,000 grant assists with insurance deductible or other flood-related expenses.
