Photo: Hozombel at English Wikipedia · CC BY-SA 3.0Flood mapping exists for Milton: 2 on record, latest by Conservation Halton
Around Milton, wildfire is practically absent from the record: 0% within 25 km since 1986, 0.000% a year. Seismic risk in Milton sits near the middle: $0.037 of expected damage per $1,000 of buildings a year, the typical town $0.030. Fewer homes than usual carry radon here, 4.1% over the guideline where the typical town has 6.6%. Hazard risk gives Milton a grade of A−, from earthquakes and radon alone.
What stands out about Milton’s hazards
Four national sources, each read for Milton: earthquakes, radon, past fires and flood studies.
What Milton faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Milton: A−
For Milton, Risk will be the average of earthquakes and radon, with wildfire added only if it makes the average worse.
Its place: #457 of 866 in Ontario and #893 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. Small fires and grass fires are largely missing from the national burned-area record.
Wildfire is rare near Milton: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where Milton’s residents live, and the fuel next to their homes.
Forty years of fire maps put Milton at 0.000% a year, low next to the typical Canadian town’s 0.000%.
Near or far, forest fuel covers a similar share around Milton: 7.9% within 5 km and 7.2% 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
To three decimals the burn rate around Milton is zero, as for 638 of the 871 towns in Ontario, while Sioux Lookout reaches 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.
Like most of Canada’s 2,610 towns (92%), Milton is in the low band, with a burn rate of zero to three decimals; 7.5% rank higher.
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.
2 flood studies cover Milton, the newest from Conservation Halton
Flood studies whose area touches Milton, from NRCan’s inventory, each linked to its owner.
Conservation Halton and others have studied flooding in areas that include Milton: 2 studies, the latest from 2020.
| Study | By | Year | Status |
|---|---|---|---|
| Halton Shoreline Flood Hazard | Conservation Halton | 2020 | final · not public |
| Grand River Regulatory Floodplain | Grand River Conservation Authority | 2018 | final |
Towns with a flood study on file
Milton 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 2 studies touching Milton are spread over time, from the 2010s to the 2020s.
Study dates as the NRCan inventory lists them, one count per study touching Milton.
Flood is shown here, never graded: a study says where a map exists, not how many of Milton’s homes stand in a flood zone.
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 Milton $0.037 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.
1.2 times the typical $0.030: Milton’s $0.037 is ordinary.
Shaking damage a year per $1,000 of building value
Neither high nor low in Ontario: Milton’s $0.037 sits by the median of $0.043, while Alexandria reaches $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.
Around half of Canada’s 2,611 towns expect more shaking damage than Milton (45%).
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).
The loss is to Milton’s buildings alone, from ground shaking; infrastructure and secondary hazards are left out.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Little radon around Milton: 4.1% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
At 4.1% over the guideline, the area around Milton is under the typical Canadian town’s 6.6%. Milton doesn’t get its own radon tests figures; the ones here come from the Halton Regional Health Unit.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Radon around Milton is ordinary for towns in Ontario: 4.1%, beside a median of 4%.
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 Milton’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.
A survey sample isn’t a map: any home in Milton can be high, and a three-month test is the only way to know.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Milton
Environment and Climate Change Canada issues the weather alerts for Milton; Alert Ready carries the urgent ones to phones, radio and TV.
| 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. |
Smoke and fire warnings for Milton come through Environment Canada and Alert Ready; the fire map is CWFIS’s.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Milton
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Milton | Low | $0.037 | 4.1% | Yes |
| Lisgar 31,627 · 10 km | Low | $0.040 | 0% | Yes |
| Churchill Meadows 48,872 · 12 km | Low | $0.040 | 0% | Yes |
| Meadowvale 37,821 · 12 km | Low | $0.040 | 0% | Yes |
| Central Erin Mills 36,393 · 14 km | Low | $0.040 | 0% | Yes |
| Oakville 243,107 · 14 km | Low | $0.045 | 4.1% | Yes |
| Erin Mills 39,194 · 15 km | Low | $0.040 | 0% | Yes |
The neighbour with the most fire is Lisgar (low), still no more than Milton (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Milton faces
Practical steps for Milton’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. A study’s area can be a whole watershed or province, so being on the inventory says a map exists, not that a home in Milton floods.
- Wildfire counts one way. Wildfire is read from the national burned-area record around Milton’s homes since 1986, a history of fire that may lower Risk but never raises it.
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Milton’s figure is its subdivision’s.
- Radon is a survey. The radon share comes from about 14,000 long-term home tests in 2009–2011, pooled for now by the 2007 health region Milton sits in.
Questions about flooding and hazards in Milton
Is Milton at risk of wildfire?
No meaningful wildfire history near Milton: 0% of nearby land since 1986, band low.
How big is the earthquake risk in Milton?
About $0.037 a year per $1,000 of building value, NRCan’s long-run expectation for Milton.
Is radon a problem in Milton?
4.1% of the 97 homes Health Canada tested around Milton topped the guideline; your own house needs its own test.
Does Milton flood?
Milton’s area has been studied for flooding, and the owner’s map shows which streets lie in a zone; the grade leaves flood out.
How is Milton’s Hazard risk Grade worked out?
Milton’s Hazard risk grade is A−, built on earthquakes and radon with a one-sided wildfire input.
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).