Photo: Quintin Soloviev · CC BY 4.0On hazards, St. Stephen comes out behind 89% of Canadian towns
Burn scars are few around St. Stephen, with 0.6% of the land within 25 km touched by fire since 1986 (0.01% a year). Shaking is a bigger worry than in most places, at $0.16 a year per $1,000 of building value ($0.030 typical). In Health Canada’s survey, 11% of homes tested in the area exceeded 200 Bq/m³ (6.6% typical). St. Stephen grades D for hazard risk, with wildfire counted against it.
What stands out about St. Stephen’s hazards
For St. Stephen, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What St. Stephen faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in St. Stephen: D
Earthquake risk and radon make St. Stephen’s grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
Its place: #48 of 60 in New Brunswick and #2,461 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Wildfire is rare near St. Stephen: 0.6% of the land within 25 km burned since 1986, 1% within 5 km
Past fire around St. Stephen’s homes, from the national burned-area record, with the fuel within 5 km.
A burn rate of 0.01% a year keeps St. Stephen in the low band (the typical Canadian town: 0.000%).
There is forest near St. Stephen’s homes (74% within 5 km) and more of it further out (86% 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 New Brunswick · highest of 60
St. Stephen sits mid-table in New Brunswick: 17th of 60 towns, at 0.01% a year, well behind Tracadie (0.28%).
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.
The low band takes in 92% of Canada’s 2,610 towns, St. Stephen among them, though its rate is above zero; 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.
St. Stephen is on the flood map inventory: 1 study, by Service New Brunswick - GeoNB
What Canada’s Flood Map Inventory lists for St. Stephen: who studied flooding and where to see their maps.
Service New Brunswick - GeoNB studied flooding in an area that includes St. Stephen (2020); open its map to see which streets lie in a flood zone.
| Study | By | Year | Status |
|---|---|---|---|
| Inland Flood Mapping in New Brunswick and Updated Sea-Level Rise and Flooding Estimates for New Brunswick Coastal Sections 2020 | Service New Brunswick - GeoNB | 2020 | final |
Towns with a flood study on file
Mapping in New Brunswick reaches 93% of towns, St. Stephen included, beside 58% across Canada.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Flood mapping is shown for St. Stephen to be opened and checked, never turned into a grade.
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 St. Stephen $0.16 per $1,000 a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
St. Stephen’s $0.16 is about 5.5 times the typical town’s $0.030: it sits in one of Canada’s more active seismic zones.
Shaking damage a year per $1,000 of building value
No town in New Brunswick expects more earthquake damage than St. Stephen ($0.16); the typical one expects $0.036.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
In the upper part of Canada’s range: 14% of its 2,611 towns expect more damage than St. Stephen.
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).
Only shaking damage to buildings in St. Stephen is counted; landslides, liquefaction, tsunami and fire after a quake aren’t.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Radon runs high around St. Stephen: 11% of tested homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
St. Stephen’s survey area reads 11% over the guideline, well past the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around St. Stephen, 11% of tests were over 200 Bq/m³, under the median in New Brunswick (20%); 1% were over 600.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
St. Stephen is in the 10–20% band, with 22% of Canada’s 2,611 towns; only 4.6% are higher.
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.
Radon varies from house to house in St. Stephen, so the survey is a reason to test, not a result for yours.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011). · Data for radon tests covers the Region 2 health region
Where to get warnings in St. Stephen
Alerts for St. Stephen 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 St. Stephen to phones; CWFIS shows the day’s fire danger.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How St. Stephen’s neighbours compare on hazards
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| St. Stephen | Low | $0.16 | 11% | Yes |
| Saint Stephen 1,772 · 4.8 km | Low | $0.14 | 11% | Yes |
| Saint David 1,559 · 7.3 km | Low | $0.14 | 11% | Yes |
| Saint James 1,085 · 15 km | Low | $0.12 | 11% | None listed |
None of the places around has more fire nearby than St. Stephen (low); Saint Stephen comes closest (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what St. Stephen faces
Practical steps for St. Stephen’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.
- Drop, cover and hold on.
- Strap the water heater down.
- Keep 72 hours of supplies.
- Has it had a radon test?
- Check the address on the flood map.
- Are flood and wildfire insured?
- Is earthquake cover included?
What this data can and can’t tell you
- Earthquakes are modelled. Seismic risk is NRCan’s model of yearly building losses from shaking, averaged over many years and given for St. Stephen’s census subdivision (a neighbourhood shows its city’s).
- Wildfire counts one way. For St. Stephen, wildfire means how much nearby land burned in the past forty years, a one-way input that can pull Risk down and nothing more.
- 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 St. Stephen.
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, St. Stephen takes its 2007 health region’s share.
Questions about flooding and hazards in St. Stephen
Is St. Stephen at risk of wildfire?
Not much by Canadian standards: St. Stephen’s band is low, with 0.6% of the land within 25 km burned since 1986 (last in 2023), so wildfire doesn’t change its grade.
How big is the earthquake risk in St. Stephen?
NRCan’s model expects shaking to cost buildings in St. Stephen $0.16 a year for every $1,000 of their value, on average over many years.
Does St. Stephen flood?
The inventory lists a study touching St. Stephen; whether a given street floods is on that map, not in the grade.
How is St. Stephen’s Hazard risk Grade worked out?
Hazard risk gives St. Stephen D, weighing earthquakes and radon and counting wildfire only against it.
Is radon a problem in St. Stephen?
11% of the 101 homes Health Canada tested around St. Stephen topped the guideline; your own house needs its own test.
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).