Photo: Krisco75 · CC BY-SA 3.0A flood study covers Ayer's Cliff: 1 on the national inventory, the newest from Gouvernement du Québec
The national fire record shows next to nothing around Ayer's Cliff, 0% of the land within 25 km since 1986 (0.000% a year). For earthquakes Ayer's Cliff is middling, $0.042 a year per $1,000 against $0.030 for the typical town. About as many homes carry radon around Ayer's Cliff as elsewhere, 7.3% over the guideline where the typical town has 6.6%. Ayer's Cliff grades B for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Ayer's Cliff’s hazards
For Ayer's Cliff, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Ayer's Cliff faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Ayer's Cliff grades B for hazard risk
Earthquake risk and radon make Ayer's Cliff’s grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. The radon share rests on 55 home tests in the survey area, so a few homes move it. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Few fires near Ayer's Cliff: 0% within 5 km, 0% within 25 km
Fires mapped since 1986 around where Ayer's Cliff’s residents live, and the fuel next to their homes.
Low: the land around Ayer's Cliff burns at 0.000% a year, where the typical Canadian town sees 0.000%.
Since 1986 the nearest fire to Ayer's Cliff’s homes came within 13 km, never inside 5 km.
30% of the land within 5 km of Ayer's Cliff is forest fuel, close to the 33% 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 Quebec · highest of 514
Of the 514 towns in Quebec, 145 have a burn rate that rounds to zero, Ayer's Cliff among them; Mistissini leads at 0.31% a year.
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%), Ayer's Cliff 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.
A flood study covers Ayer's Cliff, from Gouvernement du Québec: 1 on the inventory
Flood studies whose area touches Ayer's Cliff, from NRCan’s inventory, each linked to its owner.
For Ayer's Cliff the inventory points to Gouvernement du Québec’s 2004 study, whose map is the one to check.
| Study | By | Year | Status |
|---|---|---|---|
| Hatley | Gouvernement du Québec | 2004 | final |
Towns with a flood study on file
Only 45% of towns in Quebec have a flood study, short of Canada’s 58%; Ayer's Cliff is one of them.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Listed, not scored: a flood study proves a map exists, not that Ayer's Cliff floods.
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 Ayer's Cliff $0.042 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.
Nothing unusual about Ayer's Cliff’s ground: $0.042 against a typical $0.030, 1.4 times.
Shaking damage a year per $1,000 of building value
Earthquake risk in Quebec peaks in La Pocatière ($0.48); Ayer's Cliff, at $0.042, is below the median of $0.14.
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 Ayer's Cliff (43%).
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 Ayer's Cliff 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).
Some radon around Ayer's Cliff: 7.3% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline. · Measured across the Estrie health region: radon tests
The survey area of Ayer's Cliff reads 7.3%, a shade from the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
The typical town in Quebec has 8.2% over 200 Bq/m³; Ayer's Cliff’s area has 7.3%, much the same.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Between 5% and 10% of tests over the guideline: Ayer's Cliff, and 37% of Canada’s 2,611 towns; 26% 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.
Whatever Ayer's Cliff’s area share, the reading that matters is your own home’s, over a winter.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Ayer's Cliff
Alerts for Ayer's Cliff 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. |
Fire danger and active fires near Ayer's Cliff are mapped daily by the Canadian Wildland Fire Information System; evacuation orders come from the municipality or province.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Ayer's Cliff
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Ayer's Cliff | Low | $0.042 | 7.3% | Yes |
| Sainte-Catherine-de-Hatley 2,938 · 9.3 km | Low | $0.038 | 7.3% | Yes |
| Stanstead 1,171 · 11 km | Low | $0.039 | 7.3% | None listed |
| Magog 30,764 · 13 km | Low | $0.047 | 7.3% | None listed |
| Compton 3,351 · 18 km | Low | $0.039 | 7.3% | None listed |
| Waterville 2,643 · 19 km | Low | $0.039 | 7.3% | Yes |
| Stanstead 2,994 · 19 km | Low | $0.038 | 7.3% | None listed |
Nowhere around Ayer's Cliff burns more: Sainte-Catherine-de-Hatley, the closest rival, is low to its low.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Ayer's Cliff faces
Practical steps for Ayer's Cliff’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
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Ayer's Cliff is its health region’s, the survey’s design unit.
- Wildfire counts one way. For Ayer's Cliff, 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. NRCan’s inventory says where flood mapping exists, not where water goes; the map’s owner is the authority for Ayer's Cliff.
- Earthquakes are modelled. Seismic risk is NRCan’s model of yearly building losses from shaking, averaged over many years and given for Ayer's Cliff’s census subdivision (a neighbourhood shows its city’s).
Questions about flooding and hazards in Ayer's Cliff
Is radon a problem in Ayer's Cliff?
The area’s survey found 7.3% of 55 tested homes above Health Canada’s guideline, so a three-month test is worth doing in Ayer's Cliff.
Does Ayer's Cliff flood?
There is flood mapping for Ayer's Cliff on the national inventory, each study linked to its owner’s map, none of them graded.
How big is the earthquake risk in Ayer's Cliff?
About $0.042 a year per $1,000 of building value, NRCan’s long-run expectation for Ayer's Cliff.
Is Ayer's Cliff at risk of wildfire?
Some, but Ayer's Cliff’s low band (0% of nearby land burned since 1986, latest 2016) is short of the level that counts.
How is Ayer's Cliff’s Hazard risk Grade worked out?
Hazard risk gives Ayer's Cliff B, weighing earthquakes and radon and counting wildfire only against it.
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).