Few places are as safe from hazards as South Common: it beats 86% of Canadian towns
Wildfire barely registers for South Common, at 0% of the land within 25 km since 1986 (0.000% a year). Seismic risk in South Common sits near the middle: $0.040 of expected damage per $1,000 of buildings a year, the typical town $0.030. Fewer homes than usual carry radon here, 0% over the guideline where the typical town has 6.6%. Hazard risk gives South Common a grade of A, from earthquakes and radon alone.
What stands out about South Common’s hazards
Four national sources, each read for South Common: earthquakes, radon, past fires and flood studies.
What South Common faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in South Common: A
Seismic risk and radon set South Common’s grade, wildfire can drag it down, and flood mapping stays out of it.
Its place: #194 of 866 in Ontario and #529 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. Small fires and grass fires are largely missing from the national burned-area record.
Wildfire is rare near South Common: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where South Common’s residents live, and the fuel next to their homes.
South Common burns at 0.000% a year, low against 0.000% for the typical Canadian town.
Forest fuel is scarce around South Common: 0.6% of the land within 5 km, 1% within 25 km.
Shares of land within 5 and 25 km of populated blocks: burned at least once in 1986–2025 (CWFIS burned-area composite), forest fuel and grass (fire behaviour fuel types, 2026, 250 m grid).
Burn rate a year, towns in Ontario · highest of 871
Near-zero burning puts South Common with 638 of the 871 towns in Ontario, far below Sioux Lookout at 0.16%.
Each bar: the yearly average share of land within 25 km of a town’s homes that burned, 1986–2025 (CWFIS); the seven highest towns of 2,500 people or more.
Only 7.5% of Canada’s 2,610 towns are above the low band, which holds 92%; South Common, at a rounded zero, is far from them.
Bands of the yearly burn rate: low under 0.05%, moderate under 0.25%, high under 1%, very high 1% or more; towns of 2,500 people or more.
Fire danger and active fires (CWFIS)
Canadian Wildland Fire Information System: National Burned Area Composite 1986–2025 and fire behaviour fuel types (2026), Natural Resources Canada. Measured within 25 km and 5 km of each populated dissemination area; past fire, not a forecast.
Flooding around South Common is mapped in 3 studies, the newest by Credit Valley Conservation Authority
Flood studies whose area touches South Common, from NRCan’s inventory, each linked to its owner.
3 studies on the inventory touch South Common, the newest Credit Valley Conservation Authority’s from 2005, and their areas can be large, so they say maps exist, not that the town floods.
| Study | By | Year | Status |
|---|---|---|---|
| Credit River | Credit Valley Conservation Authority | 2005 | final · not public |
| Sawmill Creek | Credit Valley Conservation Authority | 2005 | final · not public |
| Mullett Creek | Credit Valley Conservation Authority | 1997 | final · not public |
Towns with a flood study on file
South Common is one of the 69% of towns in Ontario with a flood study on file; across Canada it is 58%.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
The studies touching South Common lean recent: 2 of 3 date from the 2000s, the first from the 1990s.
Study dates as the NRCan inventory lists them, one count per study touching South Common.
Flood studies don’t enter the grade; they are listed so you can open the official map for South Common.
The inventory’s own caution (NRCan): “The Canada Flood Map (CFM) does not include every flood hazard map in Canada and may be incomplete or contain inaccuracies. It should not be relied upon as the official source of flood mapping information. Furthermore, if a map appears to be missing, this does not necessarily mean that the area has never been mapped. For the official version of a map, updated information, or confirmation of applicable regulations, please contact the local authority responsible for flood mapping.”
Natural Resources Canada, Canada Flood Map Inventory; links go to each study’s owner.
Earthquakes cost buildings in South Common $0.040 per $1,000 a year
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
At $0.040 per $1,000, South Common’s earthquake risk is about the typical Canadian town’s ($0.030; 1.3 times).
Shaking damage a year per $1,000 of building value
South Common’s $0.040 is close to the median in Ontario, $0.043; Alexandria is highest at $0.21.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
Middle of the pack: 43% of Canada’s 2,611 towns have more earthquake risk than South Common.
Each column: the share of Canada’s towns of 2,500 people or more in that range of yearly loss per $1,000 (NRCan, 2022).
Roads, pipes and bridges aren’t in South Common’s figure, nor landslides or tsunami: it is buildings and shaking.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean). · Data for earthquake risk covers the city of Mississauga
Little radon around South Common: 0% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
At 0% over the guideline, the area around South Common is under the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
The median in Ontario is 4% over 200 Bq/m³; around South Common it is 0%.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
63% of Canada’s 2,611 towns have a higher share of homes over 200 Bq/m³ than South Common’s band, which holds 37%.
Each bar: the share of Canada’s towns of 2,500 people or more whose survey area had that share of tests over 200 Bq/m³.
The survey sampled homes around South Common; it can’t tell you your basement’s level.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011). · Radon tests: one figure for all of the Peel Regional Health Unit
Weather and fire alerts for South Common
Alerts for South Common come from Environment and Climate Change Canada and, for emergencies, Alert Ready.
| Alert | What it means |
|---|---|
| Warning | Severe weather is happening or about to: act now. |
| Watch | Conditions favour severe weather: be ready. |
| Advisory | Weather that is less severe but could disrupt the day. |
| Special weather statement | Unusual weather worth knowing about. |
| Special air quality statement | Poor air, often wildfire smoke. |
Alert Ready carries evacuation orders for South Common to phones; CWFIS shows the day’s fire danger.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How South Common’s neighbours compare on hazards
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| South Common | Low | $0.040 | 0% | Yes |
| Erin Mills 39,194 · 0.6 km | Low | $0.040 | 0% | Yes |
| Sheridan 15,775 · 2.3 km | Low | $0.040 | 0% | Yes |
| Central Erin Mills 36,393 · 3.3 km | Low | $0.040 | 0% | Yes |
| Erindale 22,755 · 3.7 km | Low | $0.040 | 0% | Yes |
| Churchill Meadows 48,872 · 4.4 km | Low | $0.040 | 0% | Yes |
| Creditview 10,972 · 4.6 km | Low | $0.040 | 0% | Yes |
The neighbour with the most fire is Erin Mills (low), still no more than South Common (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what South Common faces
Practical steps for South Common’s hazards, most pressing first.
- Test for three months in winter.
- Over 200 Bq/m³: fix it.
- Kits are cheap; pros test too.
- Never drive through floodwater.
- Move papers and medicines upstairs.
- Ask whether your street is mapped.
- Clear needles and wood nearby.
- Keep a grab-and-go bag ready.
- In smoke, stay in; filter air.
- Has it had a radon test?
- Check the address on the flood map.
- Are flood and wildfire insured?
What this data can and can’t tell you
- Flood studies aren’t flood zones. The flood inventory points to maps; it is incomplete and not the official source, so ask the municipality about any street in South Common.
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, South Common takes its 2007 health region’s share.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of South Common’s homes burned each year from 1986 to 2025, past fire rather than a forecast, and it can only lower Risk.
- Earthquakes are modelled. Shaking damage is modelled from the ground, the buildings and the odds of each quake, and published for whole subdivisions such as South Common’s.
Questions about flooding and hazards in South Common
How big is the earthquake risk in South Common?
About $0.040 a year per $1,000 of building value, NRCan’s long-run expectation for South Common.
Is radon a problem in South Common?
The area’s survey found 0% of 90 tested homes above Health Canada’s guideline, so a three-month test is worth doing in South Common.
How is South Common’s Hazard risk Grade worked out?
South Common’s Hazard risk grade is A, built on earthquakes and radon with a one-sided wildfire input.
Is South Common at risk of wildfire?
Very little by the national record: South Common’s band is low, with 0% of the land within 25 km burned since 1986, so wildfire doesn’t change its grade.
Does South Common flood?
The inventory lists a study touching South Common; whether a given street floods is on that map, not in the grade.
Seismic risk: Natural Resources Canada. Radon: Health Canada. Wildfire: Canadian Wildland Fire Information System. Flood studies: Natural Resources Canada, Canada Flood Map Inventory. Contains information licensed under the Open Government Licence – Canada.
Sources: NRCan, Canada’s Seismic Risk Model 2022 · Health Canada, Cross-Canada Survey of Radon Concentrations in Homes · CWFIS, National Burned Area Composite and FBP fuel types · NRCan, Canada Flood Map Inventory. Under the Statistics Canada Open Licence.
Adapted from Statistics Canada (Census of Population 2021, population estimates 2025, 2021 census boundaries) under the Statistics Canada Open Licence; this does not constitute an endorsement by Statistics Canada. Neighbourhood names in some cities © OpenStreetMap contributors (ODbL).