Extreme Cold Warning: What It Means and How to Stay Safe
An Arctic air mass coming down from Canada can cause temperatures to drop from mild to life-threatening in just a few hours. An Extreme Cold Warning is not only an alert to bundle up, it means extreme weather is coming. The kind of weather that can cause rapid frostbite, pipes to burst, and knock out utility grids. This guide explains what the different alerts represent and the risks they bring to your community. It also gives you steps to take to protect your home before the deep freeze arrives.
What Is an Extreme Cold Warning?
Winter forecasts frequently mention several types of cold-weather alerts that are not always clearly understood. As part of its Hazard Simplification initiative, the National Weather Service (NWS) consolidated its former wind chill products on October 1, 2024. Wind Chill Warnings became Extreme Cold Warnings, while Wind Chill Advisories became Cold Weather Advisories. These alerts may now be based on either actual air temperature or wind chill, with locally determined criteria.
Extreme Cold Warning Definition
An Extreme Cold Warning indicates that dangerously cold air temperatures or wind chill values are occurring or expected soon. The warning signals a higher level of cold-weather risk and calls for prompt protective measures, especially for people, pets, and exposed plumbing.
Temperature and Wind Chill Criteria
The NWS establishes warning criteria by local forecast area rather than using a single nationwide threshold.
For parts of the Upper Midwest & Plains (e.g., Minnesota, the Dakotas): Wind chill or air temperature thresholds may be set at −35°F or −40°F or lower, depending on the local NWS office.
For parts of the Central & Northeast States (e.g., Ohio, Pennsylvania, New York): Wind chill or air temperature thresholds can vary by location, with some areas using -20°F to -30°F or lower.
For parts of the Southern States (e.g., Texas, Georgia): Warning thresholds can be higher and vary by location.
Wind speed is a major determinant of wind chill. A 20 mph wind combined with an air temperature of 0°F produces a wind chill of approximately -22°F. In these conditions, the thin layer of warm air your body naturally produces is quickly lost.
Warning vs. Watch vs. Advisory
It helps to understand the various levels of alerts so you can take appropriate steps and know how quickly they need to be taken. Here’s a summary of the NWS cold weather alert criteria and what and when to respond.
Alert Tier | Timeline | Trigger & Action Required |
Extreme Cold Watch | 12 to 48 hours out* | Cold Weather Conditions are possible. Life-threatening cold and wind chill temperatures may develop. Begin winterizing your home, check fuel reserves, and test backup power systems. |
Cold Weather Advisory | Expected or occurring* | Unusually Cold Conditions are expected/imminent. Temperatures and wind chills will be hazardous without protection. Bundle up thoroughly, limit prolonged exposure, and protect pets. |
Extreme Cold Warning | 12 to 36 hours out or occurring* | Dangerous, life-threatening cold is occurring or imminent. Stay indoors, eliminate non-essential travel, and take immediate steps to prevent frozen pipes. |
*Timing and criteria vary by local NWS forecast office.
The differences between a “Watch” and a “Warning” here is similar to what’s used for tornado alerts. A warning is a more severe alert compared to a watch, but both are alerts.
What Does an Extreme Cold Warning Mean for Your Area?
When extreme cold affects an entire region, the impacts can extend well beyond individual homes. Cities will face a growing number of disruptions across healthcare, utilities, and transportation.
Frostbite and Hypothermia
Exposure to extreme cold can be dangerous in a matter of minutes. Frostbite occurs when the skin and deeper tissue freeze. Exposed ears, noses, fingers, and toes are common victims. Hypothermia is a condition where your body loses heat faster than it can produce it, and body temperature drops below 95°F. When this happens, confusion, slurred speech, and extreme drowsiness can set in before a person even realizes they’re in trouble.
Power Grid Strain and Service Disruptions
Space heaters, electric furnaces, and heat pumps run continuously during deep freezes, causing regional electricity demand to go to peak levels. If utility power becomes tight, or freezing rain damages transmission lines, you can expect localized blackouts. A prolonged grid failure during sub-zero conditions can turn an inconvenient outage into a critical survival situation. A home backup power plan can prioritize heating controls, refrigeration, medical devices, and communications during an outage.
Hazardous Driving and Road Conditions
Extremely cold temperatures, i.e. below 0°F, dramatically reduce the effectiveness of standard rock salt (sodium chloride) used on roads. The salt loses nearly all its melting capability once temperatures dip below 15°F. At lower temperatures, salt with special chemical additives like calcium chloride or magnesium chloride is required. This salt with additives will work on roadways effectively down to -20°F. Cold weather also reduces battery performance. At around 0°F, a vehicle battery may deliver only about half of its rated capacity, while the engine requires more energy to start.
Home and Plumbing Damage
Uninsulated pipes running inside exterior walls, crawl spaces, or unheated basements can freeze unexpectedly. As water freezes, it expands by roughly 9%, creating tremendous hydraulic pressure inside the line. A crack in the pipe can happen right at the ice blockage, at fittings or elsewhere on the pipe. This is because pressure builds throughout the pipe until the copper, PEX, or PVC splits. When this happens, it can lead to catastrophic indoor flooding once the thaw begins.
How Should You Prepare Your Home Before Extreme Cold?
Preparation is the best defense against extreme cold weather impacts. Doing a couple of hours of preparation before the cold weather hits can keep the heat inside and prevent costly emergency repairs.
Protect Pipes and Outdoor Water Lines
Disconnect and drain all outdoor garden hoses, then cover exterior spigots with insulated foam covers. An outside spigot may have a shutoff valve inside that can be closed and then leave the outside spigot open to drain. Inside, find any water lines located near exterior walls, especially in outside-facing cabinets such as under kitchen and bathroom sinks. Open the cabinet doors so warm interior air can circulate around them. If there are any faucets supplied by water pipes in exterior walls, consider maintaining a steady, trickle or drip. This is enough to keep water moving and drastically lowers freezing risks.
Inspect and Service Your Primary Heating System
Replace dirty furnace filters so your furnace runs at peak efficiency. If your home relies on heating oil or propane, check your fuel level and arrange a refill before a severe cold arrives if supplies are running low. Fuel delivery trucks can get delayed by hazardous roads. For wood-burning stoves or fireplaces, make sure the chimney has been swept to clear out soot and creosote. Keep seasoned firewood stacked close to the house under a waterproof tarp.
Seal Drafts Around Doors and Windows
Cold air will find its way inside through every way possible. Apply adhesive weatherstripping along any loose door jambs and install heavy silicone door sweeps on all exterior doors. Put up storm windows or a layer of plastic over windows, especially single-pane windows. This is one of the key steps in the winter preparedness checklist for the home and can help keep cold air out and warmth inside.
Prepare Backup Power and Emergency Supplies
Before the cold front arrives, put together an emergency supply “kit” with flashlights, fresh batteries, non-perishable foods, a manual can opener, essential medications, and at least one gallon of drinking water per person per day.
Many areas are vulnerable to winter grid failures. For these, it’s important to decide what your basic electrical needs are well in advance. If you have portable backup power stations or battery banks, make sure they are charged to 100% while wall power is still available. If the power goes out, households need to run essential loads, often simultaneously. These include a refrigerator, critical medical gear, a central heating blower or dedicated space heaters. A heavy-duty home battery system like the EcoFlow DELTA Pro Ultra Whole-Home Backup Power is a good solution during an outage. It delivers high backup power output to keep daily essentials running reliably through the outage.
What Should You Do During an Extreme Cold Warning?
Once the warning goes into effect, your attention should be on energy conservation, risk mitigation, and staying safe until the bulk of the Arctic front passes.
Monitor Weather and Emergency Alerts
Keep a battery-powered NOAA weather radio or a mobile alert app running for updates from regional emergency management agencies. Local authorities will provide information on shelter openings, when to boil water if a water main breaks, and utility updates regarding grid restoration. A portable power station can keep compatible phones, radios, and other communication devices charged during an outage.
Limit Outdoor Exposure and Travel
Stay off the roads unless an emergency forces you out. If you must go outside, wear multiple loose-fitting layers. Start with a moisture-wicking synthetic or merino wool base, an insulating fleece or down mid-layer, and a windproof, water-resistant outer shell. Mittens keep you warmer over gloves by keeping fingers together. Also, wear a hat and a balaclava or neck gaiter to prevent harsh winds from hitting your face and lungs directly.
Keep Your Home Warm and Safe
Close off unoccupied rooms, pull insulated thermal curtains closed over windows at dusk. Roll up a bath towel and put it next to exterior door thresholds to keep cold air out and warm air in.
You may be using alternative heating methods which require careful attention. Fuel-powered electric generators produce lethal levels of odorless carbon monoxide. This is why they must be used strictly outdoors, and situated at least 20 feet away from windows, doors, and fresh-air intake vents. For indoor power, you can use a portable power station like the EcoFlow DELTA 3 Max Portable Power Station that operates completely free of fuel combustion and exhaust fumes. During normal battery operation, it can support compatible electric blankets, heating pads, or small appliances indoors without producing combustion exhaust.
Check on Vulnerable Family Members and Neighbors
Elderly family members, young children, and neighbors living alone face higher risks during extended freezes. Give them a quick call or knock on their door to verify their heating system is keeping pace and their indoor temperatures are above 65°F. Also, make sure they have adequate food and warm blankets. Bring outdoor pets indoors, and check on livestock to ensure their water troughs haven’t frozen over solid.
Conclusion
An Extreme Cold Warning is a serious meteorological event. If you take the proper preparations though you can avoid the dangers they bring. Take time to winterize your plumbing, seal off drafty gaps, invest in safe indoor backup power, and stay off icy highways. This way you can keep your household warm and secure no matter how cold the weather gets.
FAQ
Can Starting Your Car in the Cold Damage It?
Yes, starting your car in severe cold can cause engine wear if you immediately accelerate hard before engine oil thins and circulates. Synthetic oils flow much better in freezing conditions than conventional oils, but letting the car idle gently for 30 to 60 seconds before driving smoothly is the safest way to bring the engine and transmission up to operating temperature.
How to Protect Lungs from Cold?
Wrap a scarf, balaclava, or thermal neck gaiter over your mouth and nose so you inhale pre-warmed, humidified air instead of harsh, dry wind. Breathing in through your nose rather than your mouth also allows your nasal passages to naturally warm and filter the air before it reaches bronchial tissue.
At What Wind Chill Is Frostbite Possible?
Frostbite can develop on exposed skin in 30 minutes or less once the wind chill index falls to -18°F under sustained winds. When the wind chill drops to -35°F or lower, skin and peripheral tissue can freeze in 10 minutes or fewer, especially on vulnerable areas like fingertips, ears, cheeks, and the nose.
What Are 5 Signs of Hypothermia?
Uncontrollable shivering (which may suddenly stop as hypothermia progresses to a critical stage)
Slurred speech or mumbling
Slow, shallow breathing and a weak pulse
Clumsiness, loss of coordination, and fumbling fingers
Confusion, memory lapses, or profound drowsiness
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