What to do if the power goes out during a winter storm with subzero temperatures

Short answer

Why people ask this

This question comes up when a winter storm knocks out electricity and the outside air is well below 0°F, making homes cool rapidly. Subzero windchill raises the risk of hypothermia, frostbite, and frozen pipes within hours. People want to know when it’s safer to stay versus go, what safe heating options exist without power, and how to protect plumbing and health. They also need clear do/don’t rules for generators, vehicles, and indoor air quality in severe cold.

When it might be safe

• The outage is expected to last under 2–3 hours and indoor temperature is still above 50°F (10°C) with minimal drafts.
• Your home is well insulated and you can consolidate into a small interior room, seal windows, and reduce heat loss quickly.
• You have an indoor-rated heater (with oxygen depletion shutoff) and a working carbon monoxide alarm, plus ventilation as directed.
• You can reach a nearby neighbor or community warming site on foot safely before windchill worsens and roads glaze over.

When it is not safe

• Indoor temperature is trending toward 40°F (4°C) or lower with subzero windchill, especially with infants, older adults, or those with medical needs.
• Using generators, charcoal grills, camp stoves, or propane heaters not rated for indoors inside the home or in an attached garage.
• Running a vehicle in an attached garage or with a snow- or ice-blocked tailpipe to keep warm.
• Relying on candles or open flames for heat, or overloading improvised heating setups near curtains or bedding.
• Attempting to drive on ice-covered roads during whiteout conditions instead of heading to the nearest walkable warming center.

Possible risks

• Hypothermia and frostbite developing rapidly in subzero windchill, even inside poorly insulated rooms.
• Carbon monoxide buildup from improper indoor heating or blocked exterior vents during drifting snow.
• Frozen and burst pipes leading to major water damage once temperatures rebound.
• House fires from unsafe space heaters, candles, or makeshift heating arrangements.
• Communication failures as phone batteries drain faster in the cold and networks are strained.

Safer alternatives

• Consolidate heat: pick one small interior room, close doors, cover windows with blankets/plastic, lay rugs, set up a tent inside, and wear layered clothing with hats and mittens; use dry towels/blankets under doors to block drafts.
• Use only indoor-rated heaters per manual (O2 depletion sensor, tip-over shutoff); keep 3 feet clear around them, crack ventilation as directed, and run a battery CO alarm; never use outdoor stoves or grills indoors.
• If roads are unsafe, warm up in a car only outdoors with the tailpipe fully cleared of snow/ice, a window slightly cracked, and the engine run 10–15 minutes each hour to conserve fuel.
• Protect plumbing: let vulnerable faucets trickle, open sink cabinets, wrap exposed pipes, and shut off/drain water lines to unheated areas to reduce freeze risk in subzero temperatures.
• Relocate early to a warming center/shelter or a friend’s well-heated home before conditions worsen; bring medications, IDs, chargers, and warm layers.

Bottom line

In subzero winter storms, act early: if you can safely keep one room warm and monitored for a short outage, shelter in place; otherwise, prioritize safe heat and air quality, protect pipes, and move to a warming center or safely run vehicle outside before indoor temperatures drop too low.

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