Severe Weather Safety: Heat Waves, Thunderstorms & Flash Floods

Extreme Heat: The Silent Killer

Extreme heat kills more Americans than any other weather event — an average of 702 people per year, according to the CDC. That is more than hurricanes, tornadoes, floods, and lightning combined. Heat-related illness is almost entirely preventable, yet it remains underestimated because it lacks the dramatic visuals of a tornado or flood. Heat kills quietly, often indoors, and disproportionately affects the elderly, outdoor workers, and people without air conditioning.

Know the Warning Signs

Heat-related illness progresses through stages. Recognizing early signs can prevent a medical emergency.

• Heat cramps: Muscle cramps, usually in the legs or abdomen, during or after physical activity in heat. Move to a cool area, hydrate with water or sports drinks, and rest. This is an early warning.
• Heat exhaustion: Heavy sweating, cold and clammy skin, nausea, dizziness, headache, fast weak pulse. Move to a cool environment, apply cool wet cloths to the body, sip water. If symptoms worsen or last more than an hour, seek medical attention.
• Heat stroke: Body temperature above 103°F, hot red dry skin (no sweating), rapid strong pulse, confusion, loss of consciousness. This is a medical emergency. Call 911 immediately. Move the person to a cool area, apply ice or cold wet cloths to the neck, armpits, and groin. Do not give fluids if the person is unconscious.

Staying Cool When It Is Dangerously Hot

• Find cooling centers. During extreme heat events, most cities open public cooling centers — air-conditioned spaces (libraries, community centers, malls) where anyone can go for free. Your city's 311 line or local emergency management website lists locations.
• Hydrate proactively. Drink water before you feel thirsty. During extreme heat, aim for at least one glass of water every 20 minutes if you are active outdoors. Avoid alcohol, caffeine, and sugary drinks — they accelerate dehydration.
• Limit outdoor activity. The highest-risk hours are 10 AM to 4 PM. If you must be outside, take breaks in shade or air conditioning every 15–20 minutes.
• Never leave anyone in a parked car. Vehicle interiors can reach 140°F within minutes on a hot day, even with windows cracked. Children and pets die from vehicular heat stroke every summer. If you see a child or animal locked in a hot car, call 911 immediately.
• Check on vulnerable neighbors. Seniors living alone, people without air conditioning, and those with chronic medical conditions are at highest risk. A phone call or visit during a heat wave can save a life.

Power Outage During a Heat Wave

A power outage during extreme heat is a compounding emergency — you lose air conditioning exactly when you need it most. Prepare for this scenario:

• Battery-powered fans provide airflow when the power is out. Keep at least one charged and ready during heat season.
• Freeze water bottles in advance. Before an expected heat wave, fill water bottles and freeze them. During a power outage, they serve as both cold packs (hold against your neck or wrists) and drinking water as they melt.
• Know where to go. If your home becomes dangerously hot during a power outage, have a plan to get to a cooling center, a friend's home with power, or a public building.
• Close blinds and curtains. Blocking direct sunlight can reduce indoor temperature by 10–15°F.

For complete power outage preparation, see our Power Outage Preparedness guide.

Thunderstorm Safety: Lightning, Wind & Power Surges

Thunderstorms are the most common severe weather event in the United States, with an estimated 100,000 thunderstorms occurring annually. Lightning kills an average of 20 people per year and injures hundreds more. Severe thunderstorms also bring damaging winds, hail, and power surges that can destroy electronics and appliances.

Lightning Safety

Lightning is unpredictable and lethal. The National Weather Service guideline is simple: "When thunder roars, go indoors."

• The 30-30 rule: If the time between seeing lightning and hearing thunder is less than 30 seconds, the storm is close enough to be dangerous. Go inside immediately. Stay inside for at least 30 minutes after the last thunder.
• Indoors is safest. A substantial building with wiring and plumbing provides the best protection (the electrical system and pipes conduct lightning to ground). Open shelters, gazebos, and picnic pavilions do not protect you.
• Vehicles are second-best. A hard-topped vehicle with the windows closed provides protection — the metal frame conducts lightning around you. Do not touch metal surfaces inside the car.
• If caught outside: Get to lower ground. Avoid hilltops, open fields, and isolated trees. Crouch low with your feet together, hands on your knees, head tucked — minimize contact with the ground. Do not lie flat.
• Avoid water. Get out of swimming pools, lakes, and off boats at the first sign of a storm. Water conducts electricity, and lightning striking a body of water can be lethal to anyone in or near it.

Protecting Your Home Electronics

A lightning strike near your home can send a massive power surge through your electrical system, destroying computers, TVs, appliances, and sensitive electronics in an instant.

• Whole-house surge protectors install at your electrical panel and provide first-line defense against surges entering through the power grid. They cost $100–$300 plus installation by an electrician. This is the single most effective step you can take.
• Point-of-use surge protectors: Plug-in surge protectors at individual outlets provide secondary protection. Look for units rated at 2,000+ joules with indicator lights that show protection status. Replace them after any major surge — they degrade with each hit.
• Unplug during storms: For maximum protection, physically unplug sensitive electronics (computers, home theater systems, routers) during active thunderstorms. No surge protector is 100% effective against a direct strike.
• Protect phone and cable lines: Surges can enter through phone, cable, and ethernet lines. Use surge protectors that include coaxial and phone line protection, or disconnect these lines during storms.

After a Thunderstorm

• Stay away from downed power lines. Assume any downed line is energized. The ground around a downed line can be electrified for 35 feet in every direction. Report downed lines to your utility company immediately.
• Check for damage. Inspect your home's exterior for damage from wind, hail, or fallen branches. Document any damage with photos for insurance purposes before making repairs.
• Test your electronics. After power is restored, check that surge protectors are still functioning (indicator light on). Replace any that took a hit.

Flash Floods: The Most Dangerous Weather Event You Underestimate

Flash floods kill approximately 145 people per year in the United States — more than lightning, tornadoes, or hurricanes in most years. More than half of flood fatalities occur in vehicles. Flash floods develop rapidly, often with little visible warning, and the force of moving water is far greater than most people realize.

Understanding Flash Flood Danger

• 6 inches of moving water can knock an adult off their feet.
• 12 inches of moving water can float and sweep away most cars.
• 24 inches of moving water can carry away trucks and SUVs.
• Flash floods can develop in minutes after heavy rain, dam failure, or rapid snowmelt. They are most common in low-lying areas, near streams, and in urban areas where pavement prevents absorption.

What to Do During a Flash Flood

• Move to higher ground immediately. Do not wait for an official warning. If water is rising in your area, move uphill now.
• Never drive through flooded roads. The NOAA mantra is "Turn Around, Don't Drown." You cannot tell the depth of water on a road, and the road surface beneath may have been washed away. If your vehicle stalls in floodwater, abandon it immediately and move to higher ground.
• Never walk through floodwater. Beyond the drowning risk, floodwater is contaminated with sewage, chemicals, and debris. It may also conceal downed power lines, open manholes, and sharp objects.
• If trapped in a building: Move to the highest floor. Do not go into an attic unless you have a way to exit through the roof — people have drowned trapped in attics as water rose. Signal for help from a window or rooftop.
• After floodwater recedes: Do not enter flood-damaged buildings until authorities declare them safe. Watch for structural damage, gas leaks, electrical hazards, and contaminated water. Photograph all damage for insurance claims before cleanup.

Flash Flood Preparedness

• Know your area's flood risk. Check FEMA's flood maps at msc.fema.gov to determine if your home is in a flood zone.
• Store emergency water before storms. A WaterBOB is a 100-gallon bladder that fits in your bathtub. Fill it before a storm to ensure clean drinking water if your supply is contaminated or cut off.
• Keep important documents elevated. Store passports, insurance policies, and irreplaceable items above the base flood elevation or in a waterproof safe.
• Flood insurance is separate from homeowner's insurance. Standard homeowner's policies do not cover flood damage. If you are in a flood-prone area, purchase flood insurance through the National Flood Insurance Program or a private insurer. There is typically a 30-day waiting period before coverage begins.

NOAA Weather Alerts & Emergency Radios

Your best early warning system for severe weather is a NOAA weather radio. Unlike smartphone alerts that depend on cell service and battery life, a dedicated weather radio receives broadcasts directly from the National Weather Service on reserved frequencies — 24/7, regardless of power outages or network congestion.

The Midland ER310 is our top recommendation. It includes:

• NOAA weather alert with SAME technology: Programs to your specific county so you only receive alerts relevant to your area — not every county in the state.
• Multiple power sources: Rechargeable battery, hand crank, solar panel, and USB charging. It works when everything else has failed.
• AM/FM radio: For general emergency broadcasts and news during extended outages.
• Built-in flashlight and SOS beacon: A 130-lumen flashlight and an SOS strobe for signaling rescue.
• USB output: Can charge your phone in an emergency (slowly, via hand crank or solar).

For complete emergency kit recommendations, see our Best Emergency Kits guide.

Understanding Weather Alert Levels

NOAA issues three levels of alerts. Knowing the difference determines how urgently you should act:

• Watch: Conditions are favorable for severe weather. Prepare your emergency supplies, charge devices, review your plan.
• Warning: Severe weather is occurring or imminent. Take action now — shelter, move to higher ground, or evacuate depending on the threat.
• Emergency: An extraordinary threat to life and property. This is the highest level. Follow all official instructions immediately.

Building a Severe Weather Emergency Plan

A plan you have practiced is worth more than a perfect plan you have never rehearsed. Every household should have a severe weather plan that covers:

• Safe rooms: Identify the safest location in your home for each type of weather — interior room on lowest floor for tornadoes, highest floor for floods, interior room away from windows for thunderstorms.
• Communication plan: Designate an out-of-area contact person who all family members can check in with. During local emergencies, local phone lines may be overwhelmed, but calls to distant area codes often go through.
• Evacuation routes: Know at least two routes out of your area in case one is blocked. Keep your vehicle's gas tank at least half full during weather season.
• Emergency supplies: Water (1 gallon per person per day for 3 days), non-perishable food, medications, flashlights, batteries, weather radio, first aid kit, phone chargers, cash, and copies of important documents.
• Pet plan: Know which shelters accept pets. Have a carrier and pet food in your emergency kit. Never leave pets behind during an evacuation.

For comprehensive emergency preparedness, visit our Emergency Prep Hub.

Weather Is Predictable — Be Ready Before It Arrives

Unlike crime, severe weather usually comes with advance warning. The tools exist — weather radios, smartphone alerts, NOAA forecasts — to give you hours or days of preparation time. The gap between surviving and suffering is almost always preparation. Invest in a weather radio, build your emergency kit, know your plan, and when the alert sounds, act immediately. The weather does not wait, and neither should you.