Prepare by imagining the unimagineable

Municipal Hazard Reference · Ottawa, ON10-Year Horizon

Doom Statistics, Locally Sourced

Four broad hazard categories, broken into their component risks, with approximate likelihood of at least one qualifying event affecting Ottawa over the next ten years. Estimates are rough, directional, and built from known regional data — not actuarial figures.

Low · under 10% Moderate · 10–40% Elevated · over 40%

01 / HYDROLOGICAL

Flood

CATEGORY LIKELIHOOD ≈ 70%

Ottawa sits at the confluence of the Ottawa, Rideau, and Gatineau rivers. Riverine flooding is the best-documented hazard in the region, reinforced by the 2017 and 2019 spring floods.

Subset	10-yr probability
Urban flash flooding / storm-sewer backupIntense rainfall overwhelming stormwater capacity, as in 2023–24 summer storms	~60%
Riverine flood (Ottawa/Rideau River)Major spring-melt flooding of the type seen in 2017 and 2019	~20–25%
Basement / overland flooding, residentialLocalized property-level flooding tied to heavy rain events	~45%
Ice-jam floodingSpring breakup jams raising water levels along tributaries	~15%
Dam / control-structure related floodingFailure or forced release affecting downstream areas	<5%

02 / AGRICULTURAL & SUPPLY

Famine

CATEGORY LIKELIHOOD ≈ 35%

Literal famine is not on the table for a Canadian capital with a diversified supply chain. The realistic subsets are food-security stress and supply disruption, not mass starvation.

Subset	10-yr probability
Sustained rise in food bank demandContinuation of the post-2020 trend in Ottawa food insecurity	~75%
Grocery supply-chain shockShort-term shortages of specific categories, e.g. pandemic-era or geopolitical disruption	~35%
Regional crop failure (Ontario/Quebec growing areas)Drought or flood-driven yield loss affecting local prices	~30%
Sharp food-price inflation eventA repeat of 2022-style inflation spikes in staples	~40%
Formal famine / mass starvation eventNot a realistic outcome for Ottawa under any current scenario	~0%

03 / BIOLOGICAL

Pestilence

CATEGORY LIKELIHOOD ≈ 80%

The broadest category by volume — driven far more by seasonal and vector-borne disease than by pandemic-scale events, though the latter is no longer a tail risk after 2020.

Subset	10-yr probability
Severe seasonal flu / respiratory-virus strainA season substantially worse than the recent baseline	~65%
Vector-borne disease expansion (Lyme, West Nile)Continued climate-driven range expansion into the region	~70%
New pandemic-scale outbreakA COVID-19-magnitude event affecting Ottawa directly	~10–15%
Waterborne illness outbreak (local)Boil-water advisory tied to contamination or infrastructure failure	~20%
Agricultural pest / crop blight (regional)Invasive insect or plant disease affecting nearby farmland	~40%
Livestock disease outbreak (regional)Avian flu or similar affecting nearby operations	~30%

04 / CLIMATOLOGICAL

Fire

CATEGORY LIKELIHOOD ≈ 85%

Ottawa itself rarely burns, but it sits downwind of boreal fire zones — the 2023 smoke events made that connection unmistakable.

Subset	10-yr probability
Wildfire smoke / air-quality eventRegional smoke advisory of 2023 severity or worse	~80%
Wildland-urban interface fire (Greenbelt/rural ward edges)Brush or forest fire reaching developed edges of the city	~20%
Major structural fire (multi-unit residential)A significant urban fire with displacement, comparable to past local incidents	~55%
Drought-driven fire-ban conditionsExtended burn bans due to dry conditions	~60%
Evacuation order from a nearby wildfireOttawa itself, not just outlying communities, placed under advisory	~8%

NOTE — figures are approximate, order-of-magnitude estimates for illustrative use, drawn from public hazard sources (ThinkHazard, City of Ottawa flood mapping, Natural Resources Canada seismic data, National Risk Profile) plus recent local event history. They are not a substitute for official emergency-management risk assessments.

Illustrative Scenario Planning · Ottawa, ONNot an official HIRA

Ten Scenarios, One Question: Is Anyone Actually Planning For This?

A municipal Hazard Identification & Risk Assessment (HIRA) exercise — the kind cities are supposed to keep current and rarely publicize. Casualty figures are illustrative, order-of-magnitude ranges drawn from comparable incidents elsewhere, not predictions built on any Ottawa-specific vulnerability data.

READ THIS FIRST — these are analogues, not forecasts. The number that actually moves a real body count isn't the initiating event — it's egress design, warning-system reliability, and response time. Treat this as a prompt for "does the city have a current, public HIRA?", not as a prediction.

Single digits Teens to ~20s Dozens or more

01

Structural collapse

Aging parking garage, construction-site failure, or overhead pedestrian bridge. Analogue: I-35W bridge, Minneapolis (2007) — 13 dead, 144 injured, caused by a design flaw combined with construction loading.

LOW–MOD

~1–15

Depends heavily on time of day / occupancy

02

Regional or commercial plane crash

Near YOW or on final approach over a populated stretch of the city. Analogue: comparable regional-jet crashes in North America.

HIGH

~10–60

Depends on aircraft size & whether it strikes populated ground

03

Fuel / hazmat tanker explosion

417 corridor, a tunnel, or a downtown intersection. Most tanker fires/explosions kill the driver and a handful of bystanders; dense crowds raise the ceiling.

LOW

~1–10

Low double digits in a worst-case dense-crowd scenario

04

O-Train collision or derailment

Ottawa's LRT has already had multiple derailments (2021–23). Analogue: comparable light-rail incidents elsewhere.

LOW–MOD

~1–15

Peak-hour crowding is the key variable

05

Rail hazmat derailment

Freight line through or near the city. Analogue: East Palestine, Ohio (2023) — zero direct deaths, but a mass evacuation and long-term exposure concerns.

LOW*

~0–5

*Direct toll often low; real cost is evacuation scale & chronic exposure

06

High-rise / multi-unit residential fire

Blocked egress or failed alarms in an aging tower. Urban apartment fires elsewhere have run from a few deaths to over a dozen when stairwells fail.

MOD

~1–20

Fire-code compliance is the deciding factor

07

Prolonged ice storm / grid failure

A repeat of 1998. That storm killed roughly 35 people across Ontario and Quebec combined, mostly from hypothermia and CO poisoning from generators.

MOD

~1–15

Ottawa's plausible share of a similar regional event

08

Extreme heat event / heat dome

Analogue: BC heat dome (2021) — roughly 619 deaths province-wide, almost entirely elderly residents without cooling access.

HIGH

~10s–dozens

Ottawa's older housing stock is the vulnerability driver

09

Ottawa River dam / control-structure failure

Rare. Comparable downstream flood-wave events have caused evacuation-scale, not mass-casualty, tolls where warning systems worked.

LOW*

~0–10

*Much higher if warning systems fail

10

Mass-casualty incident at a large public gathering

Crowd crush, vehicle-into-crowd, or targeted violence — a standard category in municipal crowd-safety and active-threat planning. Ranges vary enormously across comparable incidents.

VARIABLE

~1–dozens

Venue design & response time matter more than the trigger

WHAT THIS IS — illustrative order-of-magnitude ranges built from analogous incidents elsewhere, assembled for scenario-planning discussion. Not a prediction, not modelled against any Ottawa-specific structural, hydraulic, or crowd-density data.

THE SHARPER QUESTION — not "what could go wrong," but whether the city currently maintains and publishes a live HIRA and mutual-aid plan at all. That's a document request, not a guess.