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Heat

Table of Contents

Introduction

Extreme heat is the deadliest weather hazard in the United States, killing more people each year than hurricanes, floods, or tornadoes. Heat waves and high humidity stress the body, overwhelm critical infrastructure, and threaten vulnerable populations.

I’ve seen firsthand how quickly heat emergencies escalate: athletes collapsing at outdoor events, seniors found unresponsive in overheated homes, and children in vehicles where temperatures soared within minutes.

This guide provides a complete overview of heat hazards, how to recognize early signs of illness, and practical steps to prevent tragedy. Recommendations are based on guidance from the National Weather Service, Heat.gov, and Ready.gov.

Hazard Types

Extreme Heat / Heat Waves
Prolonged periods of high temperatures, often exceeding 90°F (32°C) for multiple days, sometimes with little nighttime cooling. These conditions place severe stress on the human body and local infrastructure.
High Humidity / Heat Index
Humidity slows the body’s ability to cool through sweating. The heat index combines temperature and humidity to show the “feels like” temperature, which may be far higher than the air temperature.
Urban Heat Islands
City environments trap and radiate heat due to pavement, buildings, and reduced vegetation. Urban areas can remain several degrees hotter than surrounding rural regions, especially at night.
Heat-Related Illnesses
Heat cramps: Painful muscle spasms caused by fluid and electrolyte loss. Heat exhaustion: Heavy sweating, weakness, dizziness, nausea. Heat stroke: A life-threatening emergency marked by confusion, hot/dry skin, and body temperature above 103°F (39°C).
Power Outages
Blackouts during heat waves cut access to fans, air conditioning, and refrigeration—further compounding health risks.
Indoor Heat
Poorly ventilated spaces, attics, and homes without AC can reach dangerous indoor temperatures, particularly for vulnerable groups.
Hot Vehicles
Temperatures inside parked vehicles rise rapidly, creating deadly conditions for children, pets, or anyone left inside—even for a few minutes.

Preparation

Before the event

  • Check daily heat and humidity forecasts; sign up for official alerts.

  • Learn symptoms and emergency actions for heat cramps, heat exhaustion, and heat stroke.

  • Identify vulnerable individuals—elderly neighbors, people with chronic illness, and households without air conditioning.

  • Locate safe cooling centers in your community (libraries, malls, official shelters).

  • Weatherize homes: install reflective shades, seal windows/doors, use insulation, and optimize fan/AC use.

  • Prepare for power outages with backup power, batteries, and generator safety.

  • Stock up on fluids, especially water; avoid alcohol, caffeine, and sugary drinks.

  • Never leave children, pets, or vulnerable individuals in vehicles under any circumstances.

Checklist essentials

Trusted forecast and heat index resources (NWS, Heat.gov, local media).
Contact list and directory of cooling centers.
Lightweight, light-colored, breathable clothing and wide-brimmed hats.
Water bottles, electrolyte solutions, cooling towels/misters.
Functional fans or AC, or arrangements to access cooled spaces.
Emergency blackout kit: flashlights, batteries, water, medications.
First-aid kit including guidance for heat illness response.

During the event

  • Stay indoors with air conditioning whenever possible.

  • If outside: wear loose, light clothing; rest frequently in shaded areas; hydrate constantly.

  • Limit outdoor activities to morning and evening; avoid midday exertion.

  • Keep blinds and shades drawn to reduce indoor heating.

  • Use cool showers, wet towels, or cooling packs to reduce body temperature.

  • Check frequently on elderly neighbors, those with chronic illness, and anyone living alone.

  • Medical guidance for heat illness:

    • Heat cramps: Stop activity, move to cool area, drink electrolyte fluids.

    • Heat exhaustion: Rest in cool place, elevate legs, hydrate; call medical help if no improvement.

    • Heat stroke: Red, hot skin; confusion; rapid pulse or unconsciousness. Call 911 immediately. Cool rapidly with water/ice, but do not give oral fluids if unconscious.

  • Pets: Provide shade, fresh water, and keep them off hot pavement.

After the event

  • Continue hydrating and avoid strenuous activity until temperatures normalize.

  • Watch for delayed effects of heat illness, especially in infants, seniors, and people with chronic conditions.

  • If power was lost, restock emergency kits and check appliances.

  • If anyone experienced heat illness, consider medical follow-up even if symptoms improved.

Special Populations

Children

Children cannot regulate heat as effectively as adults. Dress them lightly, supervise constantly, and never leave them in vehicles.

Older Adults

Seniors have a weaker thirst response and reduced ability to regulate temperature. Check frequently, ensure access to AC or cooling centers.

People with Disabilities / Medical Needs

Some medications interfere with sweating and thirst. Arrange extra support and alternative cooling strategies.

Businesses

Reschedule outdoor or physical work to cooler hours. Provide shaded breaks, water, and heat illness training for employees.

Pets

Always provide shade and cool water. Avoid walks on hot pavement and never leave pets in cars.

Quick Reference Tables

Heat Alerts and Actions
Alert Level Meaning Actions
Heat Advisory Dangerous heat likely Hydrate, limit exposure, rest indoors
Excessive Heat Warning Extreme heat imminent/ongoing Stay indoors with AC, check on vulnerable
HeatRisk (Green–Magenta) Ranges from low to extreme Take precautions according to risk level

Key Symptoms & Responses

  • Heat cramps: Rest, cool fluids.

  • Heat exhaustion: Move to cool area, hydrate, seek help if no improvement.

  • Heat stroke: Call 911, cool rapidly, no oral fluids if unconscious.

Additional notes/thoughts

Before every heat wave, ask:

  • Does everyone in my household know the symptoms of heat illness?

  • Am I checking on vulnerable relatives and neighbors?

  • Is my cooling system working, and do I have a backup plan?

  • Do I have enough water and supplies to last during a blackout?

  • Am I taking extra precautions for children and pets?

Extreme heat is becoming more common due to climate change. Preparation, vigilance, and community care are the best defenses against this silent but deadly hazard.

References

Image Credits

https://unsplash.com/photos/a-thermometer-in-the-sand-with-a-blue-sky-in-the-background-V2AMRkAUCnA

https://unsplash.com/photos/were-air-conditioned-for-your-comfort-sticker-HdIgbf03tko

https://unsplash.com/photos/white-stand-fan-turned-on-in-room-MvCW2PE9Tbg

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