thermometer icon Heat: A Major Killer
Heat Awareness Day: May 23, 2014

Sunset on a hot summer dayHeat is the number one weather-related killer in the United States.The National Weather Service statistical data shows that heat causes more fatalities per year than floods, lightning, tornadoes and hurricanes combined. Based on the 10-year average from 2004 to 2013, excessive heat claims an average of 123 lives a year.  In 2013, there were 92 heat related deaths.   By contrast the 10-year average for hurricanes is 108; floods 75; tornadoes109; and lightning 33.

In the disastrous heat wave of 1980, more than 1,250 people died. In the heat wave of 1995 more than 700 deaths in the Chicago area were attributed to heat. In August 2003, a record heat wave in Europe claimed an estimated 50,000 lives.

North American summers are hot; most summers see heat waves in or more parts of the United States. East of the Rockies, they tend to combine both high temperature and high humidity, although some of the worst heat waves have been catastrophically dry. Additional detail on how heat impacts the human body is provided under "The Hazards of Excessive Heat" heading.

NOAA's Watch, Warning, and Advisory Products for Extreme Heat

Each National Weather Service (NWS) Weather Forecast Office (WFO) can issue the following heat-related products as conditions warrant:

Excessive Heat Outlook: are issued when the potential exists for an excessive heat event in the next 3-7 days. An Outlook provides information to Heat Index forecast map for the contiguous United States those who need considerable lead time to prepare for the event, such as public utilities, emergency management and public health officials. See the mean heat index and probability forecasts maps.

Excessive Heat Watch: is issued when conditions are favorable for an excessive heat event in the next 12 to 48 hours. A Watch is used when the risk of a heat wave has increased, but its occurrence and timing is still uncertain. A Watch provides enough lead time so those who need to prepare can do so, such as cities who have excessive heat event mitigation plans.

Excessive Heat Warning/Advisory are issued when an excessive heat event is expected in the next 36 hours. These products are issued when an excessive heat event is occurring, is imminent, or has a very high probability of occuring. The warning is used for conditions posing a threat to life or property. An advisory is for less serious conditions that cause significant discomfort or inconvenience and, if caution is not taken, could lead to a threat to life and/or property.

How Forecasters Decide Whether to Issue Excessive Heat Products

NOAA's heat alert procedures are based mainly on Heat Index Values. The Heat Index, sometimes referred to as the apparent temperature and given in degrees Fahrenheit, is a measure of how hot it really feels when relative humidity is factored with the actual air temperature.

To find the heat index, look at the Heat Index Chart. As an example, if the air temperature is 96°F (found on the top of the table) and the relative humidity is 65% (found on the left of the table), the heat index--how hot it feels--is 121°F. The National Weather Service will initiate alert procedures when the Heat Index is expected to exceed 105°- 110°F (depending on local climate) for at least 2 consecutive days.Heat Index temperature chart

IMPORTANT: Since heat index values were devised for shady, light wind conditions, exposure to full sunshine can increase heat index values by up to 15°f. also, strong winds, particularly with very hot, dry air, can be extremely hazardous.

The Heat Index Chart shaded zone above 105°F shows a level that may cause increasingly severe heat disorders with continued exposure and/or physical activity.

The a heat index calculator, follow this page:  http://www.hpc.ncep.noaa.gov/html/heatindex.shtml

The Hazards of Excessive Heat

During extremely hot and humid weather the body's ability to cool itself is affected. When the body heats too rapidly to cool itself properly, or when too much fluid or salt is lost through dehydration or sweating, body temperature rises and heat-related illnesses may develop.Photo of man exhausted from playing tennis.

Heat-related illnesses can range from heat cramps to heat exhaustion to more serious heat stroke. Heat stroke can result in death and requires immediate medical attention.

Factors or conditions that can make some people more susceptible to heat-related illnesses include age (older adults and young children), obesity, fever, heart disease, mental illness, poor circulation, prescription drug and alcohol use, and sunburn. Sunburn, caused by ultraviolet radiation from the sun, can significantly retard the skin's ability to shed excess heat.

Heat-Related Illness Symptoms and First Aid

HEAT CRAMPS

  • Symptoms:
    • Painful muscle cramps and spasms usually in legs and abdomen
    • Heavy sweating
  • First Aid:
    • Apply firm pressure on cramping muscles or gentle massage to relieve spasm.
    • Give sips of water, if nausea occurs, discontinue water

HEAT EXHAUSTION

  • Symptoms:
    • Heavy sweating
    • Weakness
    • Cool, pale, clammy skin
    • Weak pulse
    • Possible muscle cramps
    • Dizziness
    • Nausea and vomiting
    • Fainting
    • Normal temperature possible
  • First Aid:
    • Move person to a cooler environment
    • Remove or loosen clothing
    • Apply cool, wet cloths
    • Fan or move victim to air conditioned room
    • Offer sips of water. If nausea occurs, discontinue water. If vomiting continues, seek immediate medical attention.

HEAT STROKE (or sunstroke)

  • Symptoms:
    • Altered mental state
    • Possible throbbing headache, confusion, nausea, dizziness, shallow breathing
    • High body temperature (106°F or higher)
    • Skin may be hot and dry, or patient may be sweating
    • Rapid pulse
    • Possible unconsciousness
  • First Aid:
    • Heat stroke is a severe medical emergency. Summon emergency medical assistance or get the victim to a hospital immediately. Delay can be fatal.
    • Move the victim to a cooler, preferably air-conditioned, environment
    • Reduce body temperature with a water mister and fan or sponging
    • Use fan if heat index temperatures are below the high 90s
    • Use extreme caution
    • If temperature rises again, repeat process
    • Do NOT give fluids

Never Leave Children, Disable Adults or Pets in Parked Vehicles

Each year children die from hyperthermia as a result of being left in parked vehicles. Hyperthermia is an acute condition that occurs when the body absorbs more heat than it can dissipate. Hyperthermia can occur even on a mild day. Studies have shown that the temperature inside a parked vehicle can rapidly rise to a dangerous level for children, adults and pets.  Leaving the windows slightly open does not significantly decrease the heating rate. The effects can be more severe on children because their bodies warm at a faster rate than adults.

Shown below is a time lapse photo of a thermometer reading in a car over a period of less than an hour. As the photograph shows, in just over 2 minutes the call went from a safe temperature to 94.3 degree F. These photos demonstrate just how quickly a vehicle can become a death trap for a child.

This graph shows hyperthermia deaths from 1998 through 2014

Hyperthermia deaths aren't confined to summer months. They also happen during the spring and fall. Below are some examples.

  • Honolulu, HI, March 07, 2007: A 3-year-old girl died when the father left her in a child seat for an 1.5 hours while he visited friends in a Makiki apartment building.  The outside temperature was only 81 degrees. 
  • North Augusta, SC, April 2006: A mother left her 15 month old son  in a car. He was in a car for 9 hours while his mom went to work. She is now serving a 20-year prison sentence.
  • Denver, CO, August 2008: Two kids that died in an overheated car may have been on their own for more than 3 hours as their mother slept after working a night shift.  The kids died in a closed but unlocked car. Investigators believe the temperature in the car may have reached 123 degrees F.

Adults are in danger too. On July 12, 2001, a man died of heatstroke after falling asleep in his car with the windows rolled up in the parking lot of a supermarket in Hinds County, MS.

How Fast Can the Sun Heat A Car?

The atmosphere and the windows of a car are relatively “transparent” to the sun’s shortwave radiation (yellow in figure below) and are warmed little. This shortwave energy, however, does heat objects it strikes. For example, a dark dashboard or seat can easily reach temperatures in the range of 180 to more than 200 degrees F.

These objects (e.g., dashboard, steering wheel, childseat) heat the adjacent air by conduction and convection and also give off longwave radiation (red) which is very efficient at warming the air trapped inside a vehicle.

Shown below is a time lapse photo of a thermometer reading in a car over a period of less than an hour. As the photograph shows, in just over 2 minutes the call went from a safe temperature to 94.3 degree F. These photos demonstrate just how quickly a vehicle can become a death trap for a child.

Objects Heated by the Sun Warm Vehicle's Air

parked vehicle

CLICK HERE FOR ANIMATION (700K)
( Hi-Res ~ 2.5 mb.WMV file)
Individual Frames:
0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min
(Animation Courtesy of General Motors and Golden Gate Weather Services)

The Law

Only 19 states have laws specifically addressing a child left unattend in a behind in a vehicle

 States that have laws

Heat Fatalities by State

In 2012 there were 32 child vehicular fatalities. So far in 2013 there was one fatality in Florida in May.

Heat Fatalities by state

Deaths for 2013

 

Heat Safety

Child Safety Tips

  • Make sure your child's safety seat and safety belt buckles aren't too hot before securing your child in a safety restraint system, especially when your car has been parked in the heat.
  • Never leave your child unattended in a vehicle, even with the windows down.
  • Teach children not to play in, on or around cars.
  • Always lock car doors and trunks--even at home--and keep keys out of children's reach.
  • Always make sure all children have left the car when you reach your destination. Don't leave sleeping infants in the car ever!

Adult Heat Wave Safety Tips

  • Slow down. Reduce, eliminate or rescheduled strenuous activities until the Thermometer reads 110 degreescoolest time of the day. Children, senior and anyone with health problems should stay in the coolest available place, not necessarily indoors.
  • Dress for summer. Wear lightweight, light-colored clothing to reflect heat and sunlight.
  • Put less fuel on your inner fires. Foods, like meat and other proteins that increase metabolic heat production also increase water loss.
  • Drink plenty of water or other non-alcohol or decaffeinated fluids. Your body needs water to keep cool. Drink plenty of fluids even if you don't feel thirsty. Persons who have epilepsy or heart, kidney, or liver disease, are on fluid restrictive diets or have a problem with fluid retention should consult a physician before increasing their consumption of fluids. Do not drink alcoholic beverages and limited caffeinated beverages.
  • During excess heat period, spend more time in air-conditioned places. Air conditioning in homes and other buildings markedly reduces danger from the heat. If you cannot afford an air conditioner, go to a library, store or other location with air conditioning for part of the day.
  • Don't get too much sun. Sunburn reduced your body's ability to dissipate heat.
  • Do not take salt tablets unless specified by a physician.

Heat Disorder Symptoms

SUNBURN: Redness and pain. In severe cases swelling of skin, blisters, fever, headaches. First Aid: Ointments for mild cases if blisters appear and do not break. If Example of a woman with severe sunburn on her back and armsbreaking occurs, apply dry sterile dressing. Serious, extensive cases should be seen by physician.

HEAT CRAMPS: Painful spasms usually in the muscles of legs and abdomen. Heavy sweating. First Aid: Firm pressure on cramping muscles or gentle massage to relieve spasm. Give sips of water. If nausea occurs, discontinue water.

HEAT EXHAUSTION: Heavy sweating, weakness, skin cold, pale and clammy. Pulse thready. Normal temperature possible. Fainting and vomiting. First Aid: Get victim out of sun. Once inside, the person should lay down and loosen clothing. Apply cool, wet cloths. Fan or move victim to air conditioned room. Offer sips of water. If nausea occurs, discontinue water. If vomiting continues, seek immediate medical attention.

HEAT STROKE (or sunstroke): High body temperature (106° F or higher). Hot dry skin. Rapid and strong pulse. Possible unconsciousness. First Aid: HEAT STROKE IS A SEVERE MEDICAL EMERGENCY. SUMMON EMERGENCY MEDICAL ASSISTANCE OR GET THE VICTIM TO A HOSPITAL IMMEDIATELY. DELAY CAN BE FATAL. White waiting for emergency assistance, move the victim to a cooler environment Reduce body temperature with cold bath or sponging. Use extreme caution. Remove clothing, use fans and air conditioners. If temperature rises again, repeat process. Do not give fluids. Persons on salt restrictive diets should consult a physician before increasing their salt intake.

For more information contact your local American Red Cross Chapter. Ask to enroll in a first aid course.

Community Guidance: Preparing for and Responding to Excessive Heat Events

The Excessive Heat Events Guidebook was developed by the Environmental Protection Agency (EPA) in 2006, in collaboration with the National Weather Service, the Centers for Disease Control and Prevention, and theDepartment of Homeland Security. This guidebook provides best practices for saving lives during heat waves in urban areas, and provides a menu of options that communities can use in developing their own mitigation plans.

This page was produced as a cooperative effort of the National Weather Service, the Federal Emergency Management Agency and the American Red Cross.

 

Resources:

too much sun means 911 Feel an Ache? Take a Break Beat the Heat If it gets hotter, drink some water Stay Hot but don't forget to cool down


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