Atmospheric River in BC: How to Prepare Your Home in Surrey

Heavy storms are a normal part of fall and winter in Surrey. Most do little harm. But strong atmospheric rivers, or several in a row, can flood streets, basements and farmland, as the November 2021 floods in southwestern BC showed.

This guide covers what an atmospheric river is, how to get official alerts, and what to do before, during and after the rain.

What is an atmospheric river?

Environment and Climate Change Canada (ECCC) describes atmospheric rivers as corridors of strong water vapour transport. They are thousands of kilometres long, up to a thousand kilometres wide, and usually last one to three days. When they reach land, the moisture falls as heavy rain, or snow in the mountains.

They are common here. ECCC's 2026 climate report cites research finding that BC and southeastern Alaska are hit by 30 to 40 atmospheric rivers each year on average, mostly in fall and winter. Most bring useful rain. The trouble comes when one is very strong, lasts a long time, or several arrive back to back on already soaked ground.

How to get official alerts

• Environment Canada weather alerts. Warnings, advisories and watches now come in colours. Yellow means hazardous weather that may cause damage or disruption. Orange means severe weather is likely to cause significant damage or disruption. Red means very dangerous, possibly life-threatening weather. Get them on the free WeatherCAN app or at weather.gc.ca. Always read the full alert text for what to do.
• City of Surrey Alertable. Surrey uses Alertable for emergency notifications. It is free. You can get alerts by app, phone, text or email. Sign up at surrey.ca/emergencynotifications and pick City of Surrey as your location.
• BC Emergency Alerts. For life-threatening emergencies, such as a high-risk flood evacuation, the Province sends alerts to TV, radio and compatible cell phones in the affected area. You don't need to subscribe. Your phone must be on an LTE or 5G network and be compatible with wireless public alerting.
• EmergencyInfoBC. The Province's source for active emergency information, including evacuation orders and alerts.

Before the storm: home prep checklist

1. Clean gutters and downspouts. The Insurance Bureau of Canada (IBC) says to clean them at least once a year. Fall, after the leaves drop, is a good time.
2. Point downspouts away from the house. PreparedBC says downspouts should extend at least 2 metres from your basement wall. IBC says at least six feet.
3. Clear the storm drains (catch basins) near your home. The City of Surrey asks residents to keep gutters and storm drains around their property clear of leaves, garbage and debris. Don't rake leaves onto the road. Only clear what you can reach safely from the curb. Never lift a grate or stand in moving water.
4. Test your sump pump, if you have one. IBC recommends a sump pump with battery backup, because heavy storms can also knock out power.
5. Check your backwater valve. A backwater valve helps stop sewage from backing up into your basement. IBC recommends installing one as your municipality advises. If you already have one, make sure it is clean and works.
6. Move valuables up. PreparedBC says to store valuables and important documents in water-tight containers or in higher places.
7. Seal low openings. PreparedBC suggests weather sealant around basement windows and the base of ground-level doors. Keep water out of window wells.
8. Check your insurance. Sewer backup and overland flood coverage are usually optional extras, not standard. Call your broker before storm season, not after.
9. Get your emergency kit ready (list below) and set up an Emergency Support Services (ESS) profile, as PreparedBC recommends.

The City of Surrey's flood preparedness page explains how to build a sandbag wall on high ground close to your home. If you need sandbags, ask the City where to get them during a flood event.

During the storm

• Report blocked City drains or street flooding. Call the City of Surrey at 604-591-4152 on weekdays, 8:30 am to 4 pm, or report it online. After hours and on weekends, call 604-591-4431.
• Cut back water use. IBC advises reducing household water use during and right after heavy rain. This eases pressure on sewers.
• Follow evacuation orders right away. PreparedBC says to monitor flood warnings, obey evacuation alerts and orders, and follow instructions from local authorities.
• Stay out of flood water. The Government of Canada says not to drive through flood waters or underpasses, because the water may be deeper than it looks. Fast water can sweep you away even if it looks shallow.
• Power out? See our guide to a BC Hydro power outage in Surrey.
• Water in the basement? See basement leak after heavy rain for step-by-step help.

After the storm

1. Go home only when it is safe. Wait until authorities say so. If the main power was not turned off before flooding, don't go in until a qualified electrician says it is safe.
2. Take photos of all damage and make a list of damaged items. IBC says to keep ruined items unless they are dangerous, and to keep all receipts.
3. Call your insurer as soon as possible. IBC's consumer line is 1-844-227-5422 if you have questions about coverage.
4. Dry out fast. The Government of Canada advises cleaning up within 48 hours if possible to avoid mould.
5. If the damage could not be insured, BC's Disaster Financial Assistance (DFA) program may help. It covers uninsurable losses from disasters with extensive or widespread damage, and only for events the Province declares eligible. Homeowners and residential tenants can apply for their principal residence. The Province says DFA pays 80% of total eligible damage less $1,000, up to $400,000. Apply within 90 days of the event being declared eligible. Call 1-888-257-4777.

PreparedBC emergency kit list

PreparedBC recommends a home kit that lasts at least three days to one week:

• Water: four litres per person, per day, for drinking and sanitation
• Non-perishable food and a manual can opener
• Battery-powered or hand-crank radio and flashlight
• First-aid kit and medications
• Copies of important documents
• Cash in small bills
• Seasonal clothing and an emergency blanket
• Whistle and dust masks

Also pack a smaller grab-and-go bag in case you must leave fast: ready-to-eat food and water, a phone charger and battery bank, a flashlight, medications, a copy of your emergency plan, and a local map with your family meeting place.

Frequently Asked Questions

Official sources

• Canada's Changing Climate Report 2026, Chapter 4 — Environment and Climate Change Canada
• Colour-coded weather alerts — Government of Canada
• Emergency Notifications — City of Surrey
• How emergency alerting works — Province of B.C.
• EmergencyInfoBC — Province of B.C.
• Getting ready before a flood — PreparedBC
• Build an emergency kit and grab-and-go bag — PreparedBC
• Flooding prevention tips for homeowners — City of Surrey
• Flood preparedness — City of Surrey
• Floods: Get prepared — Government of Canada
• Flood and water damage prevention — Insurance Bureau of Canada
• Flooding and insurance — Insurance Bureau of Canada
• Financial assistance in a disaster (DFA) — Province of B.C.

General information only, not professional advice. Rules and prices change, so check the official sources above before you act. Spotted something out of date? Tell us.