Winter storm preparedness

Winter storms kill more Americans each year than hurricanes, tornadoes, or floods. They kill people in ways that are almost entirely preventable: hypothermia in unheated homes, carbon monoxide poisoning from generators and heaters run without ventilation, and car accidents on ice. In February 2021, a winter storm knocked out power to 4.5 million Texas households for days in temperatures that dropped to single digits. More than 200 people died — the majority from hypothermia and CO poisoning, not the cold itself.

Unlike hurricanes and wildfires, winter storms rarely require evacuation. They require staying home safely. The planning problem is maintaining warmth, water, and power for 3–14 days when external infrastructure has failed.

Cold injury: frostbite and hypothermia

Hypothermia occurs when core body temperature drops below 95°F (35°C). This is not only a concern in extreme cold — hypothermia can develop at temperatures as mild as 60°F (16°C) with wind and moisture. Early symptoms include uncontrolled shivering, confusion, slurred speech, and loss of coordination. As it progresses: shivering stops (a dangerous sign — the body has lost its warming reflex), mental function deteriorates, and cardiac arrest becomes possible.

Frostbite requires air temperature below freezing, but wind dramatically accelerates tissue damage. The wind chill equivalent temperature — what exposed skin "feels" in terms of heat loss — determines how quickly frostbite develops:

Air temp	Wind speed	Wind chill	Frostbite risk
20°F (-7°C)	15 mph (24 km/h)	6°F (-14°C)	30 minutes
10°F (-12°C)	20 mph (32 km/h)	-9°F (-23°C)	30 minutes
0°F (-18°C)	20 mph (32 km/h)	-22°F (-30°C)	10 minutes
-10°F (-23°C)	30 mph (48 km/h)	-35°F (-37°C)	Under 5 minutes

Frostbite affects the extremities first — toes, fingers, ears, nose, and cheeks. The skin turns white, waxy, or grayish-yellow, and loses sensation. This is the dangerous part: frostbitten tissue doesn't hurt. Rewarm gently in warm (not hot) water, around 100–104°F (38–40°C).

Do not rub frostbitten tissue — ice crystals in the cells cause cutting damage when moved. Do not rewarm if there is risk the tissue will refreeze — a cycle of freeze-thaw causes more damage than staying frozen.

Wet clothing accelerates hypothermia faster than cold air alone

A wet cotton base layer at 50°F (10°C) with wind will produce hypothermia faster than dry insulation at 10°F (-12°C). Synthetic or wool base layers retain insulating value when wet; cotton does not. If you are working outdoors in winter conditions — clearing snow, managing livestock, doing vehicle recovery — your clothing system matters as much as the temperature outside.

Heating without grid power

The critical question during a winter power outage is: can you maintain the temperature in at least one room above 55°F (13°C) for multiple days?

Zone heating — concentrating warmth in one small room rather than trying to heat the whole house — dramatically reduces fuel demand. A single room in the interior of the house, away from exterior walls, with a door that can be closed, retains heat far better than an open floor plan. This is where your household sleeps and spends time during the outage.

Heating options during grid-down, from safest to most hazardous:

Propane or kerosene heaters (vented): Designed for supplemental heating, these are the workhorses of power outage heating when used correctly. Any heater burning fuel produces carbon monoxide — venting requirements vary by heater type, but the rule is: some source of outside air, even a cracked window of 1–2 inches (2.5–5 cm), is required to prevent CO accumulation. Keep a CO detector with battery backup in the room.

Wood stove or fireplace (with working chimney): The most reliable long-duration heat source, assuming a cord of wood is available. Inspect your chimney before winter — creosote buildup causes chimney fires. Keep the damper closed when not in use to prevent heat loss.

Catalytic propane heaters (indoor-rated): Devices like the Mr. Heater Big Buddy are rated for indoor use with ventilation. They produce minimal CO compared to open-flame heaters but still require airflow. Read the CO limitation specs; they're designed for well-ventilated spaces, not sealed rooms.

Electric space heaters: Useful during partial outages or when running a generator but pose fire risk if placed near combustibles or left unattended. Never use as primary heat during a full grid outage.

Carbon monoxide: the silent killer

Carbon monoxide (CO) is colorless and odorless. By the time you have symptoms — headache, nausea, confusion, fatigue — you may be too impaired to act.

CO concentration and effects:

CO level (ppm)	Effect
9 ppm	Maximum safe indoor level over 8 hours (EPA)
70 ppm	Headache, fatigue, nausea begin with prolonged exposure
150–200 ppm	Disorientation, risk of unconsciousness
800 ppm	Fatal in under 3 hours
1,600+ ppm	Fatal within 1 hour

In 2020, generators were responsible for 92 deaths from carbon monoxide poisoning in the US — the leading single product category for CO fatalities. The generator rule is absolute:

Never run a generator inside the home, garage, basement, or crawlspace. Never run one within 20 feet (6 meters) of any door, window, or vent. CO levels inside can reach fatal concentrations within minutes. This applies to enclosed garages even with the door open — CO travels through gaps around doors and into living spaces.

For the same reason, do not run a vehicle engine inside an attached garage to stay warm or charge a phone, and do not use gas cooking appliances as a heat source.

Field note

Install at least two CO detectors with battery backup before winter: one near sleeping areas and one near any fuel-burning appliances. Test them monthly. The combination of a generator running outside and a poorly sealed garage door has killed families who thought they were following the rules. If the CO detector sounds during a power outage, get everyone out immediately — the instinct to investigate first has cost lives.

Water supply during a freeze

Pipes freeze when temperatures inside a wall cavity drop to 32°F (0°C) and stay there. Pipes running along exterior walls and in unheated spaces (garages, attics, crawlspaces) are most vulnerable. Pipes burst when ice blockages create pressure between the blockage and the closed faucet — the burst happens downstream of the blockage, often not at the ice itself.

Prevention: - Keep heat at a minimum of 55°F (13°C) in all heated spaces, even if you are away - Open cabinet doors under sinks on exterior walls to expose pipes to room-temperature air - Let faucets drip slightly during extreme cold — moving water freezes more slowly - Know the location of your main water shutoff valve and confirm it works before winter

If pipes freeze: do not use a torch or open flame to thaw them. Use a hair dryer, electric pipe heat tape, or warm wet towels. Start thawing at the faucet end and work toward the blockage to allow melt to escape.

If pipes burst: shut off the main water valve immediately. Have the shut-off location memorized before you need it. Stored water is your backup. The water storage foundation covers how much to keep on hand and in what containers.

Vehicle and road safety

Winter driving deaths are disproportionately caused by driver behavior rather than vehicle capability. Black ice (a thin, transparent glaze of ice on pavement) forms at road temperatures of 32°F (0°C) or below, particularly on bridges, overpasses, and shaded sections of road — these areas drop to freezing before the surrounding road surface. Roads are treated with road salt at temperatures down to roughly 15°F (-9°C) — below that threshold, salt loses effectiveness and alternative treatments (sand, magnesium chloride) are used.

Emergency vehicle kit for winter driving: - Blanket rated to 20°F (-7°C) below minimum expected temperature - Jumper cables or jump starter pack - Snow shovel (collapsible) and traction boards or sand - Ice scraper and windshield de-icer - High-visibility vest and road flares - At least 1 gallon (3.8 liters) of water and food for 24 hours - Extra clothing layers including waterproof outer shell

If stranded: stay with the vehicle, which provides shelter and visibility for rescuers. Run the engine for heat no more than 10 minutes per hour, with a window cracked and the exhaust pipe confirmed clear of snow. A snow-blocked exhaust pipe concentrates CO inside the vehicle.

The power-out supply baseline

A winter storm outage is primarily an energy problem. The energy foundation covers backup power in detail — for winter specifically, prioritize:

Heat: enough fuel (propane, wood) to maintain zone heating for 7 days at minimum, 14 days as a planning target

Food: meals that don't require refrigeration and minimal cooking. Keep a 7-day supply of foods that can be eaten cold or heated on a single-burner camp stove. A full freezer that stays closed retains temperature for 48 hours; after that, assume loss.

Water: 1 gallon (3.8 liters) per person per day minimum — more if pipes freeze and tap access is lost. See water storage for container and treatment guidance.

Light: headlamps for each household member with fresh batteries; a single battery lantern for shared space. Candles introduce fire and CO risk — minimize their use.

Communication: a battery-powered or hand-crank National Oceanic and Atmospheric Administration (NOAA) Weather Radio. Cell towers lose power after 4–8 hours without backup generators. Text messages often transmit when voice calls fail — teach household members to text rather than call during outages.

Winter storm preparedness checklist

Winter storms concentrate the risks of several other foundations simultaneously: energy backup, water supply, food reserves, and medical readiness. The shelter foundation covers structural insulation and heating systems in more depth.