Ice storm: downed power lines, tree limbs, and restoring heat safely¶

An ice storm coats every surface in a layer of clear, heavy glaze. Branches snap, trees fall across roads and roofs, and power lines come down across whole regions, sometimes for days. The dangers arrive in a predictable order: first the falling limbs and live wires, then the cold house, then the rushed attempts to get warm again that start fires and cause carbon monoxide poisoning.

This guide covers the three decisions that matter most after freezing rain: how to move around a yard full of damaged trees and wires, how to stay warm when the power is out in freezing temperatures, and how to bring heat back to a cold home without hurting anyone. For the weather event itself, read ice storms, freezing rain and power line collapse. For long blackouts across a wide area, see winter power outages and prolonged blackouts.

Do this now¶

1. Stay inside until the freezing rain stops and the ice has started to melt, unless you are in immediate danger. Branches keep falling for hours after the rain ends, and they fall without warning.
2. Treat every downed line as live. Stay at least 10 meters (33 feet) away, keep children and pets back, and call your electric utility. If a line is touching a person, a vehicle or a building that is on fire, call your local emergency number (911 in the United States and Canada, 112 across the European Union, 999 in the United Kingdom). See emergency numbers for other countries.
3. Pick one room to live in. Close the door, hang a blanket over the doorway, wear layers and a hat, and move bedding in. A small room holds body heat far better than a whole house.
4. Never bring a generator, grill, camp stove or outdoor heater indoors, and never run a generator in a garage or near a window. These kill people every winter through carbon monoxide.
5. Check on neighbors who are older, ill or alone, as soon as it is safe to walk outside. Cold kills quietly, and indoor hypothermia is common in the first 48 hours of an outage.
6. Photograph damage to your home, trees and vehicles before you move anything, then report outages and damage to your utility and insurer.

Why ice storms are more dangerous than snow¶

Freezing rain falls as liquid and freezes on contact with surfaces that are at or below 0 degrees Celsius (32 degrees Fahrenheit). Even a thin layer of 0.6 centimeters (one quarter inch) of ice can add hundreds of kilograms of weight to a power line span and a large tree. The national weather agencies in the United States (National Weather Service), the United Kingdom (Met Office) and Canada (Environment and Climate Change Canada) all treat freezing rain as a high impact hazard for exactly this reason.

Ice also makes everything slippery at the same time. Roads, footpaths, steps, car doors and even the ground around your home become unsafe. If you have to move, read slipping on ice and falls first.

These ranges are general. Wind adds load, and a storm with strong wind and less ice can do the same damage as a quiet storm with more.

Downed power lines¶

A fallen wire does not have to spark, hum or move to be live. Ice storms often drop lines across driveways, fences, cars and trees, and a line can be re-energized without warning when the utility tries to restore a circuit. The ground near a downed line can also carry current, which is why you keep your distance rather than only avoiding the wire.

Keep away¶

• Stay at least 10 meters (33 feet) from any downed line, about the length of a bus.
• Do not touch anything in contact with a line, including fences, vehicles, tree branches, puddles and metal gutters.
• Do not try to move a line with a stick, a broom or a shovel. Wood, plastic and fiberglass can still conduct when wet or iced.
• Keep children and animals inside until you have walked the yard from a distance.
• Warn others by calling out, closing a gate or placing a clear marker at a safe distance. Do not stand near the line to guard it.

If a line falls on your vehicle¶

Stay inside the vehicle and call your local emergency number. Warn anyone approaching to stay back. The only reason to leave is a fire. If you must leave, open the door, keep your hands in front of you, and jump clear with both feet together so you are not touching the car and the ground at the same time. Then shuffle away with small steps, keeping your feet together and on the ground, to avoid a difference in voltage between your feet. The full steps are in downed power lines and vehicle electrocution. If a line lands on your house or yard, also read fallen power line on house or yard fence.

Who to call¶

Report downed lines to your electric utility first when no one is hurt. Call your local emergency number when a line is across a road, touching a person or vehicle, causing a fire, or when someone has been shocked. In the United Kingdom, the number for network faults is 105, which connects you to your local network operator. In other countries, find your utility's emergency line on your last bill and save it in your phone before storm season.

Tree limbs and falling ice¶

Ice weighs down branches, then wind and sun release them. A limb that has survived the night can fall the next afternoon as the temperature climbs and the ice softens. Many injuries after ice storms come from people walking under trees to inspect damage or to clear driveways.

Moving around the yard¶

1. Wait until the ice starts dripping or shedding before you go outside, and then look up before every step.
2. Stay out from under large trees, utility lines and the eaves of the roof. Ice sheets slide off steep roofs and can be heavy enough to injure.
3. Wear boots with a deep, soft tread, or add traction cleats. See the footwear section in slipping on ice and falls.
4. Walk with short steps, with your feet flat and your hands free. Do not carry loads that block your balance.
5. Keep a charged phone in an inside pocket where it stays warm, and tell someone where you are going.

Hazard trees and hanging limbs¶

Look for hanging branches, called widowmakers, caught in the crown of a tree. Look for trees leaning more than usual, root plates lifted from the soil, split trunks, and large cracked limbs still attached by a strip of bark. Do not stand beneath any of these, and do not park under them.

What you should not do¶

• Do not cut a tree that is under tension, leaning on another tree, or tangled with a power line. Cutting releases stored energy, and the cut piece can spring back or roll.
• Do not climb a ladder in icy conditions to cut or knock off limbs.
• Do not use a chainsaw if you are not trained, are cold and tired, or have no one nearby. Chainsaws injure thousands of people after storms. See chainsaw kickback and widowmaker tree felling injuries.
• Do not shake or beat ice off branches. The branch can snap, and the ice falls toward you.
• Do not touch any tree that is near or on a power line. Trees and branches conduct electricity.

Hire a licensed arborist or your local tree crew for anything that is on a house, a line or a road. Many places also run storm cleanup help through local government or volunteer groups. Be careful of door to door offers right after a storm, because scams spike after disasters. Ask for ID, a written estimate and proof of insurance, and do not pay the full amount in advance.

If a tree has hit your house¶

Get everyone out of the damaged area and stay clear of any room under the tree. A damaged roof may fail without warning, and a broken electrical service entrance can leave live wires in the walls. If you smell gas, hear hissing or see sparks, leave the house and call the utility and your local emergency number from outside. Once everyone is safe, read tree on house for the next steps.

Surviving a freezing power outage¶

When the power goes out in freezing temperatures, your home loses heat steadily. Even a well insulated house can fall to near outdoor temperature in a day or two. Your plan has four parts: preserve heat, protect the people who are most at risk, avoid dangerous heat sources, and stay informed.

Preserve the heat you have¶

• Choose the smallest, best insulated interior room with the fewest outside walls and windows. A bathroom, hallway or interior bedroom works well. Avoid basements in floods and avoid rooms with a lot of glass.
• Close doors to the rest of the house. Block drafts under the door with towels and rolled blankets.
• Cover windows with blankets, towels, cardboard or heavy curtains. Tape plastic sheeting over any cracked or leaking windows.
• Close fireplace dampers when the fireplace is not burning.
• Put on layers: a base layer, a warm middle layer, and a windproof outer layer. Wear a hat and warm socks, because a large share of body heat leaves through the head and feet.
• Sleep in a group, under several blankets, on a mattress or a pad rather than directly on the floor.
• Eat regularly and drink warm fluids. Food is your internal heater. Avoid alcohol, which feels warming but speeds heat loss.

Know who is at greatest risk¶

Babies, adults over 65, people with heart disease, diabetes or thyroid problems, people who take sedating medicines, and anyone who is already unwell can develop hypothermia in a house that feels merely cool. See hypothermia and frostbite for the warning signs. The older adults section later in this guide covers when to check on neighbors, and keeping older adults safe in cold weather goes deeper.

Safe heat sources¶

Use only heat sources that are designed for indoor use, with the right fuel, and with working alarms. A battery powered carbon monoxide alarm and a working smoke alarm are the minimum. For a full breakdown of what to use and what to avoid, see space heaters, fireplaces and wood stoves in an outage.

If you have no safe heat source and the house falls below about 10 degrees Celsius (50 degrees Fahrenheit), the safest move is to go somewhere warm. Options include a friend or relative with power, a public warming center, a community shelter, or a hotel. Your local government usually announces warming centers on its website, local radio, or through a hotline. In the United States, you can call 211 for local shelter information.

Keep the water from freezing¶

When the power is out, pipes can freeze in a day or less on a hard cold night. Open cabinet doors below sinks so warm air reaches the pipes, let a faucet drip, and know where your main water shutoff is. See frozen pipes for prevention and thawing, and for what to do if a pipe has burst.

Food, water and medicine¶

A closed refrigerator keeps food safe for about 4 hours, a full freezer for about 48 hours, and a half full freezer for about 24 hours. In freezing weather, you can store food outdoors in a covered container that animals cannot reach, but keep it from freezing and thawing repeatedly. Do not eat anything that has been above 4 degrees Celsius (40 degrees Fahrenheit) for more than 2 hours. See spoiled food and fridge power outage. If you rely on medicine that needs refrigeration, check temperature sensitive medications in a power outage.

Never melt snow for drinking unless you have to, and then boil it for at least 1 minute. Do not use snow that is discolored or near roads. Also remember that refrigerated medicines such as insulin can be damaged by freezing.

Powering devices¶

Phone batteries drain faster in the cold. Keep phones close to your body, turn on low power mode, lower the screen brightness, and send brief text messages rather than making long calls. A power bank charged before the storm is worth more than most other storm purchases. Battery powered radios, preferably with hand crank and weather band, give you official updates when cell towers fail.

Using a generator safely¶

A generator is the largest single cause of carbon monoxide deaths after winter storms. Carbon monoxide is odorless and colorless, and a running generator can fill a house with a lethal level within minutes. The key rules follow CDC (United States) and Health Canada guidance.

• Run a generator outdoors only, at least 6 meters (20 feet) from the house, with the exhaust pointed away from windows, doors and vents.
• Never run it in a garage, even with the door open, in a basement, a crawlspace or a shed. Never run it on a porch or under a carport attached to the house.
• Install a battery powered carbon monoxide alarm in every sleeping area and on every floor.
• Keep the generator dry, under an open canopy if there is snow. Do not cover it in a way that blocks the exhaust or the air intake.
• Plug appliances directly into the generator with heavy duty outdoor cords, or have a licensed electrician install a transfer switch. Never plug a generator into a wall outlet, which can send power back into the lines and kill line workers.
• Let the generator cool down before you refuel it, and store fuel outside the living space.

For fuller guidance read generator safety. For symptoms and treatment of poisoning, see carbon monoxide and carbon monoxide and smoke inhalation first aid.

Restoring heat safely¶

When power returns, the rush to get warm creates new hazards. Pipes may have frozen, appliances may have been left on, and a house that has been cold for days can behave differently once the furnace runs again. Go slowly and check each system.

Before the power returns¶

If you have to leave your home during a long outage, turn off the main water supply and drain the system if you know how. When you stay, switch off or unplug heating appliances, stoves and other items that you were using, so they do not start on their own when the grid returns. Leave one lamp on so you know when power is back. This also helps prevent a surge when everything starts at once.

First hour after power is restored¶

1. Turn the thermostat up gradually, perhaps 2 or 3 degrees Celsius (about 5 degrees Fahrenheit) at a time. A big jump makes your system work harder and may trip breakers.
2. Look and listen at your furnace or boiler. If you smell gas, hear hissing, or smell something burning, leave and call your gas utility and your local emergency number. Do not flip switches on the way out.
3. Check the pilot light or ignition system, as per the manufacturer's instructions. Do not relight a pilot light if you smell gas.
4. Walk through the house and look for drips, wet ceilings, bowed walls and sagging floors. Frozen pipes may have split and begin to leak only as they thaw.
5. Turn on appliances one at a time, not all at once. Wait a few minutes between large loads such as water heaters, ovens and dryers.
6. Check your carbon monoxide alarm and smoke alarm by pressing the test button.
7. Open faucets slowly to see if water flows. If a pipe is frozen, do not use a torch or open flame. Warm it gently with a hairdryer, with the faucet open, working from the faucet toward the frozen section.

Check the chimney and flue¶

Chimneys that have been unused, iced over or hit by branches can be blocked. If you plan to use a fireplace or stove for the first time since the storm, check the chimney cap and the flue for ice, debris or nests. See chimney fire and creosote hazard. A blocked flue pushes smoke and carbon monoxide into the house, so open the damper, light a small test fire only if you are sure the flue is clear, and stay awake.

Water heater and pipes¶

After a long cold outage, a water heater or tank may have a frozen supply line, a damaged pressure relief valve, or a cracked tank. Do not switch on an electric water heater until the tank is full of water, because heating an empty tank can burn out the elements. See water heater failure if you see leaks, rust colored water, or hear banging noises.

Warm the people, then the house¶

Warm people before the house, if someone has been very cold. Bring them into a warm room, remove any wet clothing, wrap them in dry blankets, and give warm sweet drinks if they are awake and can swallow. Do not rub their skin, and do not put them in a hot bath. If they are shivering violently, confused, very sleepy, or stopped shivering, call your local emergency number. Read hypothermia and frostbite for the full steps.

Decision flow after an ice storm¶

flowchart TD
    A["Ice storm has passed"] --> B{"Are any lines down<br/>near you?"}
    B -->|"Yes"| C["Stay 10 meters or 33 feet away<br/>and call the utility"]
    B -->|"No"| D{"Is power on?"}
    C --> D
    D -->|"Yes"| E["Check pipes, heater and flue<br/>then turn heat up slowly"]
    D -->|"No"| F{"Is the house above<br/>10 C or 50 F?"}
    F -->|"Yes"| G["Shelter in one room<br/>and use safe heat only"]
    F -->|"No"| H["Move to a warming center<br/>or a relative with power"]
    G --> I{"Anyone with headache,<br/>dizziness or confusion?"}
    I -->|"Yes"| J["Go outside into fresh air<br/>and call emergency number"]
    I -->|"No"| K["Check on neighbors<br/>and keep listening for updates"]

Comparing heat sources in an outage¶

Checking in on others¶

Ice storm outages tend to isolate people. Once you are safe, check on neighbors who live alone, anyone who relies on powered medical equipment, and people with limited mobility. Knock on doors from the path, call by phone first, and do not enter a home you cannot see into if you smell gas or smoke. If someone is unreachable and you are worried, call your local emergency number and ask for a welfare check.

If you rely on a ventilator, oxygen concentrator or CPAP machine, see power outage for oxygen concentrators, ventilators and CPAP. Tell your utility in advance if someone in your home depends on powered medical equipment. Many utilities keep a priority list, such as the Priority Services Register in the United Kingdom, though a place on the list does not guarantee power.

Pets and animals¶

Bring pets indoors and keep them in your warm room. Cats and dogs can freeze, and ice and salt hurt paws. Wipe paws after a walk and check for cracks or bleeding. Provide fresh water that is not frozen, and keep antifreeze and de-icing chemicals out of reach, since they are toxic. For livestock and larger animals, check water sources and windbreaks as soon as it is safe. See pets in emergencies.

Driving after an ice storm¶

Avoid driving until crews have cleared and treated the roads. If you must go, drive slowly, with large gaps between vehicles, and keep a winter kit in the car. Steer into a skid, brake gently, and never use cruise control on ice. Watch for tree limbs and wires, and do not drive over a line, even if it looks dead. Treat dark intersections as four way stops when the signals are out. See flash freeze and black ice driving and car emergency kit.

Cleaning up and recovering¶

When the ice melts, the cleanup begins. Take your time, work with a partner, and take breaks to warm up. Overexertion in the cold is a real heart risk. If you are shoveling heavy slush or ice, read shoveling snow safely.

• Wear gloves, eye protection and sturdy boots.
• Pile debris away from the house and out of the way of utility crews.
• Do not burn wet debris against a house or under power lines.
• Keep a record of damaged items and repairs for insurance. Keep receipts for emergency costs such as hotel stays, ice and meals, because some policies reimburse them.
• Check your roof for ice damage and falling limb damage once the ice has melted. See roof leak.

Checklist for the first day after the storm¶

• Everyone is inside and warm, with dry clothes and a hat.
• All downed lines are reported, and no one is within 10 meters (33 feet) of them.
• A battery powered carbon monoxide alarm is working.
• No generator, grill or camp stove is in the house, garage or near windows.
• Phones are charged or in low power mode, and a radio is ready.
• Neighbors who are older, ill or alone have been checked on.
• Food in the fridge and freezer has been checked and kept cold.
• Water has been protected from freezing, and the main shutoff is known.
• Pets are inside with water and shelter.
• Photographs of damage have been taken.

Frequently asked questions¶

How far should I stay from a downed power line after an ice storm?¶

Stay at least 10 meters (33 feet) away, which is about the length of a bus, and treat every line as live even if it is lying still or looks dead. Do not touch anything that is in contact with the line, such as a fence, a tree or a car. Call your electric utility, or your local emergency number if the line is across a road, on a vehicle, or has injured someone.

Is it safe to heat my house with the oven or a gas stove during a power outage?¶

No. A gas oven or stove burner is not designed to heat a home, and it produces carbon monoxide that can build up in a closed room without any smell. Use only heaters made for indoor use, keep a battery powered carbon monoxide alarm in every sleeping area, and go to a warming center if you cannot keep the house warm safely.

How long can I stay in a house without heat in freezing weather?¶

It depends on the house, the outdoor temperature and the people inside. Babies, older adults and people with medical conditions can become ill in a home that is only cool, so move them to a warmer place early. If the indoor temperature falls toward 10 degrees Celsius (50 degrees Fahrenheit) and you cannot raise it safely, go to a relative, a hotel or a warming center instead of waiting.

When is it safe to turn the heat back on after a long outage?¶

Turn it on once you have checked for gas smells, leaks, frozen or split pipes, and a blocked chimney or flue. Raise the thermostat in small steps rather than all at once, and turn on large appliances one at a time. Test your smoke and carbon monoxide alarms, and call a licensed technician if your furnace, boiler or water heater behaves in a way that worries you.

Sources checked¶

Guidance in this page was checked against the following official sources: the National Weather Service (United States) winter weather safety pages, the Centers for Disease Control and Prevention (United States) guidance on carbon monoxide and generators and on staying safe in cold weather, Ready.gov and the Federal Emergency Management Agency (United States) winter storm and power outage guidance, the American Red Cross winter storm safety pages, the Met Office and the UK Health Security Agency (United Kingdom) cold weather advice, the National Health Service (United Kingdom) advice on keeping warm, and Health Canada and Public Safety Canada guidance on winter storms and carbon monoxide. Where agencies use slightly different distances or times, this guide gives the more cautious number.

Learn first aid¶

Reading helps, but a hands-on first aid course teaches you to act when it counts. The Red Cross, St John Ambulance and many local providers run short courses in first aid, CPR and treating cold injuries. Book one before the next winter, and take someone from your household with you.

Related guides¶

• Ice storms, freezing rain and power line collapse
• Winter storm safety: home heating and cold survival
• Downed power lines and vehicle electrocution
• Hypothermia and frostbite
• Frozen pipes