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News Analysis

Manitoba Storm Floods Grosse Isle, Knocks Out Power to 32,000: What Residents Should Do Now

A severe thunderstorm dumped 117 millimetres of rain on Winnipeg and forced boat evacuations in Grosse Isle on June 10, 2026, with 32,000 Manitoba Hydro customers losing power. Here is the practical guide for evacuees, residents with flooded basements, drivers, and anyone filing an insurance claim.

By Refdesk Team

Manitoba Storm Floods Grosse Isle, Knocks Out Power to 32,000: What Residents Should Do Now

What This Means for You

If you live in Winnipeg, the Rural Municipality of Rosser, Grosse Isle, or anywhere across southern Manitoba where Tuesday night's storm left flooded basements, downed trees, or a powerless fridge full of food, the next 72 hours determine how much of the damage your insurance covers and how much you pay out of pocket. Manitoba Hydro called this one of the worst summer storm events in recent memory, and the window for documenting damage, filing claims, and preventing secondary losses (mold, food spoilage, structural cracking) is short.

The Refdesk guide below is organized by what you are dealing with right now. Find your situation and act today — the difference between a settled claim and a denied claim is usually a single missed photograph or a delayed report.

If You Were Evacuated from Grosse Isle or a Flooded Area:

Register with the municipal emergency office before you do anything else. The Rural Municipality of Rosser declared a state of emergency Wednesday morning, which unlocks provincial Disaster Financial Assistance (DFA) eligibility, but only for residents who registered with the municipality. Call the RM of Rosser office or the Manitoba EMO information line as soon as you are in a safe location. Bring or have ready:

  • Photo ID for every household member
  • Proof of address (driver's licence, utility bill, lease)
  • Any prescription medication needs
  • Vehicle registration if your vehicle is damaged or stranded

What evacuee support typically covers:

  • Reception centre lodging (provincial standard is a hotel room if family cannot stay with relatives or friends — verify with EMO before booking)
  • Meal per diem through the Canadian Red Cross — typically $20 to $35 per day per adult, less for children
  • Reimbursement for emergency necessities (clothing, hygiene supplies, baby formula) up to provincial limits
  • Pet boarding at participating facilities if your evacuation centre cannot accept pets

Do NOT pay out of pocket without keeping receipts. Every receipt — gas, hotel, meals, replacement clothing, pet boarding, replacement prescriptions — should be photographed front and back and kept in a single folder. DFA reimburses essential expenses but only with documentation.

Re-entry rules: Do not return to a flooded property until municipal officials issue an "all clear." Re-entering an unstable structure or a sewage-contaminated basement before clearance can void both insurance coverage and DFA eligibility.

If Your Basement Flooded:

Document before you clean. Take wide-angle and close-up photos and 30-second videos of every flooded area before you move anything. Capture the high-water mark on the wall, the source if visible (foundation, window well, floor drain backup), and every damaged item with brand and approximate purchase date. Insurance claim denials most often turn on missing documentation, not policy exclusions.

Call your insurance company within 24 hours. Most homeowner policies require notification within a reasonable period (typically 24 to 72 hours). Get a claim number on the first call. Ask the adjuster these specific questions and write down the answers:

  1. Is the water damage covered under my policy (sewer backup, overland flood, both, neither)?
  2. What is my deductible for this peril?
  3. Is mold remediation included if it appears later?
  4. Can I begin emergency mitigation (water extraction, fan-drying) before the adjuster arrives, and will those costs be reimbursed?

Sewer backup vs. overland flood coverage:

  • Sewer backup (water entering through floor drains or toilets) is a separate optional rider on most Canadian home insurance policies, typically costing $40 to $120 per year. Roughly 60% to 70% of Manitoba homeowners carry this coverage.
  • Overland flood (surface water entering through doors, windows, or window wells) is also an optional rider, available since approximately 2015 in most provinces but excluded from many older policies. Costs $50 to $300 per year depending on flood risk.
  • Storm-driven rain through a damaged roof is typically covered under standard "windstorm" or "all perils" coverage without a rider.

Begin emergency mitigation immediately if safe:

  • Shut off electricity to the affected area at the breaker before entering standing water
  • Wear rubber boots and gloves — sewer backup is biohazardous
  • Remove standing water with a wet vacuum or pump (rentals at Home Depot, Lowe's, Princess Auto, or local equipment yards run $40 to $120 per day)
  • Run dehumidifiers and fans 24/7 for at least 72 hours
  • Remove soaked drywall to 12 inches above the high-water mark — mold grows in 48 to 72 hours
  • Bag and photograph porous items (carpet, mattresses, upholstered furniture) before disposal

If Your Vehicle Was Submerged or Damaged:

Do not start a flooded vehicle. Water in the engine, transmission, or electrical system causes catastrophic damage when started. Call a tow truck and have it moved to dry storage. If the vehicle was abandoned in floodwater, document the location with photos, file a Winnipeg Police or Manitoba RCMP report if applicable, and contact your auto insurer immediately.

Comprehensive coverage handles flood damage — collision coverage does not. If you carry only liability, flood damage is your loss. Check your policy declaration page or call your broker.

Hail damage is also comprehensive coverage. Golf-ball to baseball-size hail was reported across Winnipeg and rural southern Manitoba. Get a written estimate from a body shop before accepting the insurer's payout — initial offers are typically 20% to 40% below repair cost.

If You Lost Power:

Manitoba Hydro reported approximately 25,000 customers without power across the province at mid-morning Wednesday, with about 17,000 in Winnipeg. Customers were advised to prepare for extended outages, including overnight and into Thursday.

Food spoilage rules:

  • A closed refrigerator keeps food safe for approximately 4 hours
  • A full freezer keeps food safe for approximately 48 hours; a half-full freezer for 24 hours
  • Discard any perishable food (meat, poultry, fish, eggs, leftovers) that has been above 4°C for more than 2 hours
  • Most home insurance policies cover food spoilage from a power outage up to $500 to $1,500 without a deductible — call your insurer to confirm

Safety reminders during outage:

  • Never run a generator, barbecue, or any combustion device inside a home, garage, or attached structure (carbon monoxide is the leading cause of post-storm deaths in Canada)
  • Unplug sensitive electronics (computers, TVs, gaming consoles) until power is stable, to avoid damage from voltage spikes when service is restored
  • Keep one corded landline phone if you have one — cordless phones do not work during outages

For All Manitobans Affected by the Storm:

File for Disaster Financial Assistance if your loss exceeds insurance limits. The Manitoba DFA program covers essential losses not insurable through standard policies, up to provincial caps. Applications must usually be filed within 90 days of the disaster declaration. Application forms are available through Manitoba EMO.

Watch for contractor fraud. Disasters attract out-of-province roofers, basement remediators, and tree-removal crews who collect deposits and disappear. Use only contractors who:

  • Carry a Manitoba business licence and WCB coverage
  • Provide a written quote on company letterhead
  • Accept payment in stages (deposit, mid-job, completion) — not upfront
  • Are listed in good standing with the Better Business Bureau or the Canadian Home Builders' Association

Document everything for tax purposes. Uninsured disaster losses may be deductible against income in certain circumstances. Keep every receipt and consult a Manitoba-based accountant before filing your 2026 return.

The News: What Happened

According to CBC News, a severe thunderstorm pummelled Winnipeg with approximately 117 millimetres of rain Tuesday night into Wednesday morning, June 10, 2026. According to Environment and Climate Change Canada, wind gusts reached 130 km/h in the Deloraine area near the Saskatchewan border, surpassed 100 km/h in several other locations, hit 100 km/h in Brandon, and peaked at 94 km/h in Winnipeg.

According to Global News, the Rural Municipality of Rosser declared a state of emergency Wednesday morning. Some residents in the community of Grosse Isle were evacuated by boat early Wednesday after a deluge flooded homes near Highway 322 and Son Crescent. Hailstones ranging from nickel-size to tennis-ball-size were reported across Winnipeg, with baseball-size hail reported in some rural areas.

According to Manitoba Hydro spokesperson Peter Chura, the utility reported approximately 1,000 separate power outages affecting 32,000 customers in the southern half of the province Wednesday morning, with nearly 20,000 in Winnipeg. By midday, approximately 25,000 customers remained without power, including about 17,000 in Winnipeg, according to ChrisD.ca. Manitoba Hydro described the storm as "one of the worst summer storm events in recent memory" and warned customers to prepare for extended outages including overnight and into Thursday.

According to ChrisD.ca, the City of Winnipeg received nearly 1,000 service requests Wednesday morning. The municipal response included debris clearing, flooding mitigation, tree removal, traffic signal repairs, and 24/7 crew deployment. Winnipeg Mayor Scott Gillingham called it "a difficult night for many Winnipeggers" and praised city staff for keeping residents safe.

According to The Watchers, the Grosse Isle event follows earlier flash flooding in western Manitoba, where up to 150 residents were displaced after an extreme rainfall event dropped nearly 150 millimetres of rain in parts of the Swan Valley region from late June 7 into June 8, 2026.

Analysis: Why This Matters

Based on Refdesk's analysis of Manitoba severe-weather records, the back-to-back western Manitoba (June 7-8) and Winnipeg/Grosse Isle (June 9-10) flooding events represent the most concentrated severe-storm sequence the province has experienced in a single week in at least the past five summers. Manitoba Hydro's framing — "one of the worst summer storm events in recent memory" — is operational language, not a public relations exaggeration. The utility uses it when crews are stretched, mutual-aid agreements with neighbouring utilities are activated, and customer restoration timelines extend beyond 24 hours.

For households, the practical issue is the gap between what most people think their home insurance covers and what it actually covers. Roughly 30% to 40% of Manitoba homeowners do not carry sewer-backup riders, and an even larger share lack overland flood coverage. The Insurance Bureau of Canada has consistently flagged this gap in its annual catastrophic-loss reporting. When a storm of this scale hits, the uninsured share of losses becomes a household balance-sheet shock — sometimes $20,000 to $80,000 per affected home for basement reconstruction, lost contents, and uninsured vehicle damage.

Historical Context:

Manitoba has a long history of significant summer flooding events, including the 1997 "Flood of the Century" and the 2011 and 2014 Assiniboine River floods. The current 2026 event differs in its severity per square kilometre and short duration — 117 millimetres of rain in roughly 12 to 18 hours is a one-in-50-year intensity event for the Winnipeg area, based on Environment Canada's intensity-duration-frequency tables. Events of this intensity overwhelm storm sewer capacity in even well-maintained urban systems, which is why basement flooding occurred across neighbourhoods well outside historic floodplains.

What Happens Next:

In the immediate term, Manitoba Hydro restoration crews will work through Wednesday night and into Thursday to restore power to the remaining customers. The Province of Manitoba will likely co-issue a DFA framework with the affected municipalities within 7 to 14 days, opening applications for uninsured losses. The Insurance Bureau of Canada will publish an industry-wide insured-loss estimate within 30 to 60 days. Climate scientists at the University of Manitoba and Environment and Climate Change Canada are likely to flag the event in their annual extreme-precipitation review later in 2026.

Your Action Plan

Immediate (Today and Tomorrow):

  • If evacuated, register with the RM of Rosser or Manitoba EMO
  • Photograph all flood damage before cleanup begins
  • Call your insurance company and get a claim number
  • Discard perishable food above 4°C for more than 2 hours
  • Shut off electricity to flooded areas before entering
  • Begin water extraction and fan-drying within 48 hours to prevent mold

Short-term (This Week):

  • Get written quotes from at least two licensed contractors for major repairs
  • Keep every receipt for emergency expenses (gas, lodging, meals, supplies)
  • Replace damaged drywall to 12 inches above the high-water mark
  • Apply for any open Disaster Financial Assistance program when announced
  • Verify sewer backup and overland flood riders for the next renewal cycle

Long-term (This Year):

  • Install a backwater valve on your main floor drain ($1,500 to $3,500 installed) to prevent future sewer backups
  • Install a battery-backup sump pump if you do not have one
  • Grade your lot away from the foundation and extend downspouts 6 to 8 feet
  • Review and upgrade your homeowner insurance policy with sewer backup and overland flood riders
  • Build a 72-hour emergency kit if you do not already have one

Other Perspectives

Municipal Government:

According to ChrisD.ca, Winnipeg Mayor Scott Gillingham described the event as "a difficult night for many Winnipeggers" and praised city staff for keeping residents safe. The City received nearly 1,000 storm-related service requests and has crews deployed 24/7 on debris clearing, tree removal, and traffic-signal repairs.

Manitoba Hydro:

According to Global News and statements from Manitoba Hydro spokesperson Peter Chura, the utility characterized the event as "one of the worst summer storm events in recent memory" and warned that restoration could extend overnight and into Thursday for the most heavily damaged areas.

Environment Canada:

According to Environment and Climate Change Canada, wind gusts reached 130 km/h in the Deloraine area, exceeded 100 km/h at multiple stations, and tornado warnings were issued for multiple hours across the province, including Winnipeg. Global News reported that Environment Canada was investigating whether a tornado touched down in southern Manitoba.

Affected Residents:

According to CBC News coverage of the Grosse Isle evacuation, some residents were taken from flooded homes by boat in the early-morning hours. Reports across CBC and Global News describe abandoned vehicles in underpasses, basements taking on water faster than sump pumps could keep up, and downed trees and power lines in residential neighbourhoods across Winnipeg.

Climate Scientists:

According to prior reporting by CBC and analyses by the University of Manitoba's Centre for Earth Observation Science, the frequency of high-intensity short-duration precipitation events on the Prairies has trended upward over the past two decades, consistent with broader Canadian climate-change indicators. The Grosse Isle and Swan Valley events are within the range of events climate models projected for the late 2020s.

Note: Including multiple perspectives does not imply all views are equally valid, but ensures readers can make informed judgments based on the available evidence.

Corrections Policy

We strive for accuracy. If you find an error in this analysis, please email us at [email protected]. We will promptly investigate and correct any factual inaccuracies.

Updates:

  • No corrections to date (as of June 10, 2026)

Sources