Photo: Kmsiever · Public domainA flood study covers Lethbridge: 1 on the national inventory, the newest from Government of Alberta
Wildfire is a moderate presence around Lethbridge: 2.2% of the land within 25 km has burned since 1986, 0.06% a year, short of the band that counts against Risk. Seismic risk in Lethbridge sits near the middle: $0.025 of expected damage per $1,000 of buildings a year, the typical town $0.030. Lethbridge’s survey area, 8.9% over the radon guideline, is close to the typical town’s 6.6%. Hazard risk gives Lethbridge a grade of B; its wildfire band pulls it down.
What stands out about Lethbridge’s hazards
Four national sources, each read for Lethbridge: earthquakes, radon, past fires and flood studies.
What Lethbridge faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Lethbridge grades B for hazard risk
Earthquake risk and radon make Lethbridge’s grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
Its place: #449 of 474 in Alberta and #1,515 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.
Some fire around Lethbridge: 2.2% of the land within 25 km since 1986, 3.7% within 5 km
Past fire around Lethbridge’s homes, from the national burned-area record, with the fuel within 5 km.
Moderate: the land around Lethbridge burns at 0.06% a year, where the typical Canadian town sees 0.000%.
Around Lethbridge the forest is thin or far off: 0% of the land within 5 km and 0% within 25 km is forest fuel.
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 Alberta · highest of 478
Lethbridge ranks 36th of the 478 towns in Alberta for burn rate, at 0.06% a year; Wainwright leads with 1.43%.
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.
Moderate puts Lethbridge above most of Canada’s 2,610 towns, yet 2.1% rank high or very high and 5.4% share its band.
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.
Government of Alberta has mapped flooding for Lethbridge (1 study)
What Canada’s Flood Map Inventory lists for Lethbridge: who studied flooding and where to see their maps.
For Lethbridge the inventory points to Government of Alberta’s 2007 study, whose map is the one to check.
| Study | By | Year | Status |
|---|---|---|---|
| Lethbridge Flood Hazard Study | Government of Alberta | 2007 | final |
Towns with a flood study on file
Its flood study sets Lethbridge apart in Alberta, where 46% of towns have one (Canada: 58%).
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 Lethbridge 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.
Ordinary seismic risk in Lethbridge: $0.025 per $1,000 of buildings a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
0.8 times the typical $0.030: Lethbridge’s $0.025 is ordinary.
Shaking damage a year per $1,000 of building value
The typical town in Alberta expects $0.013 a year; Lethbridge expects $0.025, and Black Diamond $0.048.
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: 53% of Canada’s 2,611 towns have more earthquake risk than Lethbridge.
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 Lethbridge’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).
Some radon around Lethbridge: 8.9% of area homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline. · Area-wide: radon tests, counted over the Chinook Regional Health Authority
Around Lethbridge, 8.9% of tested homes topped the guideline, near the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Lethbridge’s area, at 8.9%, is close to the median in Alberta (7.5%); 0.9% of its tests passed 600 Bq/m³.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Radon tops the guideline in a modest share of homes around Lethbridge, a band holding 37% of Canada’s 2,611 towns; 26% rank above.
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 Lethbridge 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 Lethbridge
Alerts for Lethbridge 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 Lethbridge to phones; CWFIS shows the day’s fire danger.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Lethbridge
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Lethbridge | Moderate | $0.025 | 8.9% | Yes |
| Coalhurst 3,244 · 8.5 km | Moderate | $0.029 | 8.9% | None listed |
| Coaldale 9,644 · 16 km | Low | $0.027 | 8.9% | None listed |
| Lethbridge County 10,988 · 18 km | Low | $0.024 | 8.9% | Yes |
Coalhurst burns a little more than Lethbridge, in the same moderate band (moderate here).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Lethbridge faces
Practical steps for Lethbridge’s hazards, most pressing first.
- Clear needles and wood nearby.
- Keep a grab-and-go bag ready.
- In smoke, stay in; filter air.
- 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.
- Has it had a radon test?
- Check the address on the flood map.
- How close is the forest edge?
- Are flood and wildfire insured?
What this data can and can’t tell you
- Flood studies aren’t flood zones. NRCan’s inventory says where flood mapping exists, not where water goes; the map’s owner is the authority for Lethbridge.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Lethbridge’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 Lethbridge’s.
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Lethbridge is its health region’s, the survey’s design unit.
Questions about flooding and hazards in Lethbridge
Is radon a problem in Lethbridge?
8.9% of the 112 homes Health Canada tested around Lethbridge topped the guideline; your own house needs its own test.
Does Lethbridge flood?
There is flood mapping for Lethbridge on the national inventory, each study linked to its owner’s map, none of them graded.
Is Lethbridge at risk of wildfire?
Not much by Canadian standards: Lethbridge’s band is moderate, with 2.2% of the land within 25 km burned since 1986 (last in 2012), so wildfire doesn’t change its grade.
How big is the earthquake risk in Lethbridge?
In NRCan’s seismic model, Lethbridge’s buildings lose $0.025 per $1,000 of value in an average year.
How is Lethbridge’s Hazard risk Grade worked out?
Lethbridge grades B for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers 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).