10 ways to prepare your home for a wet El Niño winter

Most winter storms come with a few days of forecast warning at best. El Niño works on a longer clock. It is a shift in ocean and atmospheric conditions that forecasters monitor as it builds in the tropical Pacific. That lead time gives households a chance to act before the rain starts rather than after water is already inside.

El Niño is the warm phase of the El Niño–Southern Oscillation, a recurring climate pattern often shortened to ENSO. During this phase, sea surface temperatures in the central and eastern equatorial Pacific run above average. Those warmer waters shift weather patterns far beyond the ocean. In winter, El Niño tends to steer more rain toward the southern U.S., including Southern California.

That word "tends" matters. El Niño raises the odds of a wet season across a broad region. It does not guarantee one in any particular town or neighborhood. The NOAA Climate Prediction Center issues the official seasonal outlooks. The National Weather Service handles local forecasts. Following both gives homeowners a regional view and a local one.

Preparation also has a financial side. Standard homeowners insurance policies generally exclude flood damage. Flood coverage is sold separately through the National Flood Insurance Program or private insurers. NFIP policies generally carry a 30-day waiting period before coverage begins. A policy bought once storms appear in the forecast may not take effect in time.

Much of the remaining work is ordinary home maintenance done on a deadline. Gutters, roofs, yard grading and sump pumps all affect where rainwater goes once it reaches a property. A small problem in any of them can let water collect against a foundation or seep through a ceiling. Repairs are easier to schedule and carry out in dry weather than in the middle of a storm.

This guide on how to prepare your home for El Niño covers 10 practical steps. They are a selection, not a complete checklist. They span insurance, roof care, drainage and the yard. They also cover emergency supplies for power outages and the records and habits that speed recovery if water gets in. Each slide stands on its own, so readers can start with the step that fits their home and their timeline.

Illustration: Quartz

An El Niño winter outlook signals higher odds of a wet season across the southern U.S., including Southern California. It does not promise rain in any single town. Local forecasts still decide what a household should expect as storms approach.

El Niño is the warm phase of a recurring Pacific climate cycle. NOAA tracks it in a band of the equatorial Pacific known as the Niño 3.4 region. An El Niño is declared when ocean temperatures there sit at least 0.5 degrees Celsius above normal and the atmosphere responds in step.

That warm water changes how air moves over the Pacific. During El Niño winters, the Pacific jet stream tends to strengthen and shift farther south than usual. More storms then tend to track across the southern tier of the country, from California through the Gulf Coast to Florida.

The northern U.S. often sees a different pattern. The Pacific Northwest and the Ohio Valley tend toward drier winters, and much of the northern tier runs warmer than average. A homeowner in Seattle and one in San Diego can read the same El Niño headline and face very different seasons.

Even in the south, the wet pattern is not assured. Some El Niño winters have brought less rain to parts of California than the seasonal odds suggested. The strength of an event matters. Other weather patterns can also override the Pacific signal in a given month.

The NOAA Climate Prediction Center publishes an ENSO diagnostic discussion each month. Its alert system has two main stages. An El Niño Watch means conditions favor one forming, and an El Niño Advisory means one is underway. The center's seasonal maps show the chances of above-, near- or below-normal precipitation rather than rainfall totals.

Local National Weather Service offices handle the forecasts that matter on a given day. They issue flood watches when flooding is possible and flood warnings when it is happening or about to happen. Signing up for alerts from the local office, or turning on emergency alerts on a phone, closes the gap between a seasonal outlook and an actual storm.

Illustration: Quartz

A standard homeowners policy generally excludes flood damage. Coverage for rising water is a separate purchase, and most National Flood Insurance Program policies take effect only after a 30-day waiting period.

That gap is why timing matters. A homeowner who waits until a storm shows up in the forecast will usually still be uninsured when the water arrives. Buying in late summer or early fall gives the waiting period time to pass before the wettest months of an El Niño winter.

The National Flood Insurance Program is run by FEMA, the Federal Emergency Management Agency. Homeowners do not buy its policies from FEMA directly. Insurance agents sell them, and private insurance companies write and service the federal policies on the government's behalf.

The program splits protection into two parts. Building coverage pays to repair the structure itself, including the foundation and systems such as electrical wiring, plumbing and furnaces. Contents coverage pays for belongings such as furniture, clothing and electronics. For a residential property, the NFIP caps building coverage at $250,000 and contents coverage at $100,000. Renters can buy contents coverage on its own.

Basements get limited treatment under NFIP policies. Building coverage there extends to equipment such as furnaces, water heaters and sump pumps. Finished flooring, paneling and most belongings stored below ground level are generally not covered.

Private flood insurance is the other route. Private carriers set their own terms, limits and waiting periods. Some offer higher limits than the federal program, or coverage for items the NFIP excludes. Comparing a private quote with an NFIP quote side by side shows which terms fit a given home.

Flood risk is not confined to mapped high-risk zones. FEMA's flood maps mark Special Flood Hazard Areas. Federally regulated or insured lenders require flood insurance on mortgaged homes inside those areas. Homes outside them can still flood during heavy rain. Owners there can buy a policy even when no lender requires one.

The 30-day rule has narrow exceptions. One applies to coverage bought in connection with making, increasing, extending or renewing a mortgage loan. A homeowner relying on any exception should confirm the policy's effective date in writing with the agent.

Illustration: Quartz

Clearing clogged gutters and aiming downspouts away from the house keeps roof runoff from pooling beside the foundation. It is a basic step in El Niño flood preparation that most homeowners can handle before the first heavy storm.

A roof collects rain across its whole surface and funnels it into a few narrow channels. Leaves, pine needles, twigs and shingle grit can block those channels. When they do, water backs up and spills over the edge. It then lands in a line along the base of the walls. Repeated soaking there can push moisture toward basements, crawl spaces and slab edges.

Start by scooping out debris by hand or with a gutter scoop, working from a stable ladder. Bag the material instead of dumping it into flower beds against the house. Piled there, it holds moisture right where the gutters are meant to keep water away. Then run a garden hose into each gutter. Water should move toward the downspout instead of standing in low spots.

The hose test also exposes other problems. Drips from seams point to failed joints that need resealing. Gutters that sag or pull away from the fascia board may need new hangers or brackets. If little or no water comes out of the downspout outlet, the downspout itself is usually clogged. That blockage can often be cleared from the bottom or flushed from the top.

Where the downspout empties matters as much as the gutter. A downspout that drains straight onto the ground at a corner of the house undoes much of the gutter's work. Extensions carry the water outward. Common options include splash blocks and hinged or flexible extension pipes. Buried drain lines can move the water farther across the yard. As general guidance, aim each outlet several feet from the foundation. Point it toward ground that can absorb or carry the flow, not toward a walkway or a neighbor's property.

Gutters under heavy tree cover can refill quickly in late fall. Homeowners in those yards may need to clear them more than once before and during the rainy season. Mesh or screen guards cut down on large debris. They still need periodic checks for fine material that collects on top.

Illustration: Quartz

A pre-season roof inspection should look for three trouble spots: damaged shingles, failing flashing and worn sealant. A small leak caught in dry weather costs less to fix than the interior water damage it can cause once winter storms arrive.

Start with the shingles. A missing shingle leaves the underlayment and roof deck below it exposed. A cracked shingle lets water seep through the break. Shingles that curl at the edges or cup in the middle no longer lie flat, and wind-driven rain can work its way underneath them. Curling is common on older asphalt roofs that have spent years in the sun.

Much of this damage is visible from the ground. A pair of binoculars and a slow walk around the house can reveal missing tabs, bare patches and lifted edges. Work on a steep or wet roof is safer left to a licensed roofer with proper fall protection.

Flashing is the next check. Flashing is the thin metal that seals the joints where the roof meets a chimney, a vent pipe, a skylight or an adjoining wall. These seams are where many roof leaks begin. Look for flashing that has bent, pulled away, rusted through or worked loose from its fasteners.

Plumbing vent pipes often pass through the roof inside a rubber or neoprene collar, sometimes called a pipe boot. That rubber can crack and split with age. A failed boot lets rainwater run down the outside of the pipe and into the attic.

Sealant is the third item. The roofing sealant and caulk around flashing, vents and skylights dry out and shrink over time. Gaps, cracks or brittle, peeling beads mean the seal has failed. The old material needs to be scraped away and replaced.

The attic offers a view from the other side. On a dry day, shine a flashlight along the underside of the roof deck. Water stains, dark streaks, damp insulation or pinpoints of daylight all point to a problem above. Brown rings on upstairs ceilings are another sign that water has already found a way in.

Illustration: Quartz

Soil around a house should slope down and away from the foundation. The International Residential Code sets a minimum fall of six inches within the first 10 feet. Correcting a flat or reversed slope helps keep winter rain out of basements and crawl spaces.

When the ground tilts toward a house, every storm sends runoff straight to the foundation walls. Water that pools there soaks into the soil beside the walls. From there it can work its way through cracks, joints and gaps around pipes. In a crawl space, it can leave standing water and damp framing.

Grading problems often develop slowly. Soil that was dug out and replaced around a foundation during construction tends to settle in the years afterward. That settling can turn a slope that once drained well into a shallow trench that holds water against the house. Raised planting beds, thick mulch and landscape edging can trap runoff in the same way.

Checking the slope takes only basic tools. Drive one stake into the ground at the foundation and a second stake 10 feet straight out. Tie a string between them, level it with a line level and measure from the string down to the ground at each stake. The ground at the outer stake should sit at least six inches lower than the ground at the house.

Where the slope falls short, homeowners can build it up by adding fill soil against the foundation. The new soil can then be finished with topsoil and grass or plants. Added soil should stay below siding and wood framing. Burying those materials invites rot and insects.

Some lots are too tight for a full 10-foot slope, such as houses close to a property line or a neighboring wall. The code allows drains or swales in those cases. A swale is a shallow, grass-lined channel that carries water around the house and away from it. Patios, walkways and driveways next to the house should also tilt away from the foundation.

Fill soil only holds a slope if it is packed firmly. Wet clay is heavy and sticky, and it resists compaction. Loose fill can settle and recreate the low spot it was meant to fix. Regrading is a job for the dry weeks before the rainy season.

Illustration: Quartz

A sump pump should be tested before the rainy season by pouring water into its pit until the float switch rises and the motor starts. A battery backup keeps the system working when a storm knocks out power.

A sump pump sits in a pit, often called a sump basin, dug into the lowest point of a basement or crawl space. Groundwater collects in that pit. Perimeter drain pipes laid around the foundation often feed it. When the water level climbs, a float rides up with it and trips a switch. The pump then pushes the water out of the house through a discharge pipe.

The test mirrors what happens during a heavy rain. Fill a bucket and pour it slowly into the pit. Watch the float lift and listen for the motor to engage. The pump should empty the pit and then shut off on its own once the float drops. If the motor hums without moving water, or never starts at all, the pump needs repair or replacement before storms arrive.

A few related checks fit into the same visit. Confirm the pump is plugged in and the outlet has power. Unplug the unit before reaching into the basin. Then look for gravel, silt or other debris in the pit that could jam the float or clog the intake. Follow the discharge pipe outside and make sure its outlet is clear of leaves and soil.

Many discharge lines also include a check valve. This one-way valve stops pumped water from draining back into the pit after the motor shuts off. A failed valve can make the pump cycle on and off repeatedly.

The weak point of a standard sump pump is electricity. Heavy rain and high wind often arrive together. The same storm that sends water into a basement can also cut power to the house. A primary pump without power does nothing.

A battery backup system addresses that gap. It typically adds a second pump with its own float switch. That pump runs on a rechargeable battery, which a charger keeps topped up. If the main pump loses power or fails, the backup takes over. Many units also sound an alarm when they activate. Rechargeable batteries lose capacity as they age. Test the backup whenever the main pump gets tested.

Illustration: Quartz

Fill each sandbag about half full, close it and lay the bags flat in tight, overlapping rows. A well-built line can steer shallow runoff away from doors and low openings. Sandbags do not create a watertight seal.

The half-full rule matters. An overstuffed bag turns rigid and round. That shape leaves gaps between neighboring bags that water can push through. A bag with room to spare flattens under its own weight. It then settles against the bags beside and beneath it.

Placement starts with the spots where water would get in first. Doorways, garage doors, basement window wells and low points along an exterior wall are the usual targets. The aim is to send runoff around the house toward an area where it can drain away. A sandbag line is not built to hold back a rising flood.

Lay the first row with the bags end to end, pressing each one firmly against the last. Stagger the next row so each bag covers the joint between two bags below it. The pattern works the way bricks overlap in a wall. Press or tamp each bag down as it goes into place to close air pockets. A taller barrier needs a wider base to stay stable.

Some homeowners put down plastic sheeting on the water side of the line before stacking. The sheeting slows seepage through the fabric and the joints. Some water can still get through.

Filled sandbags are heavy. Filling and moving them is easier with two people and a pair of work gloves. Setting the line up before a storm arrives avoids hauling bags through rain and mud.

Local governments in flood-prone areas often provide sand and empty bags to residents. What is offered, and where, differs from place to place. A city or county public works or emergency management office can say what is available nearby.

After the water recedes, bags that sat in floodwater may carry sewage or chemicals. Handle them with gloves and check with the local government on how to dispose of them.

Illustration: Quartz

Dead trees, leaning trees and heavy limbs can come down when soil is saturated and winds pick up. An arborist's assessment before storms arrive, plus moving loose outdoor items, lowers the risk to the house, cars and neighboring property.

Waterlogged ground is the core of the problem. Roots anchor a tree by gripping the surrounding soil. After days of rain, that soil turns soft and holds the roots less firmly. A gust a tree would normally ride out can then pull it over or snap a heavy limb.

A tree that already leans or carries decay has less margin to begin with. Some warning signs are visible from the ground. They include dead or leafless branches, deep cracks in the trunk, cavities or hollow sections and mushrooms or other fungi growing near the base.

Soil that cracks or lifts on one side of the trunk can mean the roots are shifting. Limbs hanging over the roof, the driveway or a bedroom should be checked first. A failure in those spots carries the highest cost.

An arborist can judge which trees need pruning, cabling or removal. The International Society of Arboriculture runs a certification program for arborists. Homeowners can use its directory to find certified professionals in their area.

Branches growing into or near power lines are a separate case. Homeowners should not prune near energized lines themselves. The local electric utility handles trimming around its lines or can say who is responsible.

Outdoor furniture and loose items need attention too. Heavy rain can turn a sloped yard or street into a channel of moving water. That runoff can carry off patio chairs, cushions, planters, children's toys and trash bins.

Items swept away can block drains or pile up against fences and neighbors' homes. Strong wind can also lift light objects and drive them into windows.

Small items can go into a garage, shed or basement before a storm. Larger pieces that stay outside can be tied down or grouped against a wall, out of the wind. Propane tanks should stay upright and secured outdoors, never stored inside the home.

Illustration: Quartz

An emergency kit should hold at least one gallon of water per person per day for at least three days, according to Ready.gov. A portable generator can keep essentials running during a storm outage, but it must never run indoors or inside a garage.

Heavy winter rain can knock out power and close roads at the same time. A stocked kit lets a household stay put until utilities and travel return to normal.

Water makes up the bulk of the kit. A family of four needs at least 12 gallons to meet the three-day minimum. Store it in sealed containers in a cool, dark place.

Ready.gov also recommends flashlights and a battery-powered or hand-crank radio. A radio still receives emergency broadcasts when cell service and home internet go down. Extra batteries belong in the kit as well.

Ready.gov's basic supply list goes further. It includes a supply of nonperishable food and a manual can opener. It also lists a first aid kit and a whistle to signal for help.

Medications need their own plan. Prescriptions can run low if pharmacies close or roads flood. Check refills before the rainy season starts. Keep phone chargers and a backup battery in the same container.

Store everything in one easy-to-carry bin in a dry, accessible spot. Review it once a year and replace expired food, water and batteries.

Generators bring a separate risk. Their engines produce carbon monoxide, a gas with no color or smell. In an enclosed space, it can kill within minutes.

Running a generator indoors or in a garage is never safe. Open doors and windows do not clear the gas fast enough to prevent poisoning.

Place the generator outside, well away from doors, windows and vents that could draw exhaust into the house. Install battery-powered carbon monoxide alarms, or plug-in units with battery backup. Those alarms keep working when the grid is down.

Learn the warning signs. The CDC lists headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion as common symptoms of carbon monoxide poisoning. Anyone who feels ill near a running generator should move to fresh air and call 911.