Heat Waves

Heat Index Chart / NWS Alert Procedures
A
heat wave is an extended interval of abnormally hot and usually
humid weather, usually lasting from a few days to over a week.
Heat waves
form when an air mass becomes stationary over a region. Hot humid air masses
form over the Gulf of Mexico and the Caribbean Sea while hot dry air masses
form over the desert Southwest and northern Mexico. In the Eastern United
States a heat wave occurs when a high pressure system originating in the
Gulf of Mexico becomes stationary just off the Atlantic Seaboard (typically
known as a Bermuda High.) The SW winds on the back side of the High continue
to pump hot, humid Gulf air North-eastward resulting in a spell of hot and
humid weather for much of the Eastern States.
Heat Waves are
dangerous because heat kills by taxing the human body beyond its abilities.
In a normal year, about 175 Americans succumb to the demands of summer heat.
Among the large continental family of natural hazards, only the cold of
winter - not lightning, hurricanes, tornadoes, floods, or earthquakes -
takes a greater toll. In the 40-year period from 1936 through 1975, nearly
20,000 people were killed in the United States by the effects of heat and
solar radiation. In the disastrous heat wave of 1980, more than 1,250 people
died. The July 1995 heat wave caused more than 1,000 heat-related deaths
across the Midwest and East Coast. And these are the direct casualties. No
one can know how many more deaths are advanced by heat wave weather - how
many diseased or aging hearts surrender that under better conditions would
have continued functioning.
A heat
advisory is issued when the heat, or combination of heat and humidity,
is expected to become an inconvenience for much of the population, and a
problem for some.
An
excessive heat warning is issued when the heat, or combination of heat
and humidity, is expected to be dangerous for a large portion of the
population.
The heat
index is the number in degrees Fahrenheit that tells how hot it really
feels when relative humidity is added to the actual air temperature.
Exposure to full sunshine can increase the heat index by 15 degrees
Fahrenheit.
 |
130 degrees or higher:
|
heatstroke/sunstroke highly likely
with continued |
| 105 - 130 degrees: |
sunstroke, heat cramps or heat
exhaustion likely with prolonged exposure. |
| 90 - 105 degrees:
|
sunstroke, heat cramps and heat
exhaustion possible with prolonged exposure and/or physical activity.
|
| 80 - 90 degrees: |
fatigue possible with prolonged
exposure and/or physical activity. |
The National
Weather Service (NWS) will initiate alert procedures when the heat index is
expected to exceed 105 -110 degrees Fahrenheit for at least two consecutive
days.
Are You at
Risk?
Extreme heat
is more than an issue of discomfort. It forces the body into overdrive as it
tries to stay cool through perspiration and evaporation. People in urban
areas are at greater risk because the stagnant atmospheric conditions trap
pollutants in the air, which, when breathed can trigger respiratory problems
for many people.
The effects of
extreme heat can undermine you physical well being so slowly and subtly that
the dangers aren't apparent until it's too late. Heat can effect anyone,
however, it is more likely to affect young children, elderly people, and
people with health problems. (Example - A medical condition that causes poor
blood circulation and those who take medicine to get rid of water from the
body {diuretics} or for certain skin condition, may be more susceptible.
Consult a physician if you have any questions about how your medication may
affect your ability to tolerate heat).
In regions of
low humidity, the most common human response to extreme heat is
dehydration. Exposed to direct sunlight and temperatures in excess of 90
, a human can lose as much as half a gallon of water every ten minutes, and
this dehydration can seriously interfere with one's internal thermostat.
Heat-Related Illnesses
- Severe Sunburn - so much more that a
dermatological issue, sunburn reduces the skin's ability to release excess
heat, making the body more susceptible to heat-related illnesses.
- Heat Cramps - muscle pains and spasms caused by
heavy exertion, which triggers loss of water through heavy perspiration.
These usually involve the muscles of the abdomen or legs.
- Heat Exhaustion - a mild form of shock marked by
heavy sweating, weakness, cold, clammy skin, a weak pulse, fainting and
vomiting. This usually occurs when people have been exercising heavily or
working in a warm humid place. The blood flow to the skin increases -- in
an attempt to cool the body -- causing the blood flow to the vital organs
to decrease. If not treated the victim's condition will worsen. Body
temperature will keep rising and the victim may suffer heat stroke. Simple
overexposure to extreme heat can precipitate this condition in very young
children and the elderly.
- Heat Stroke (also called Sunstroke) - a truly
life-threatening condition in which the body's internal thermostat has
ceased to work. The victim's temperature control system, which produces
sweating to cool the body, stops working. The body temperature can rise so
high that brain damage and death may occur in less than ten minutes unless
medical help is immediate.
Signs and
Symptoms to Look For:
- Heat Cramps - Painful spasms usually in muscles
or legs and abdomen. Heavy sweating.
- Heat Exhaustion - Cool, moist, pale or flushed
skin, heavy sweating, headache, nausea or vomiting; dizziness; and
exhaustion. Body temperature will be near normal.
- Heat Stroke - Hot, red skin; changes in
consciousness; rapid, weak pulse; and rapid, shallow breathing. Body
temperature can be very high, sometimes as high as 105 . If the person was
sweating from heavy work or exercise, skin may be wet; otherwise, it will
feel dry. Treatment for These Conditions:
- Heat Cramps - Get the person to a cooler
place and have him or her rest in a position of comfort. Give a half of
glass of cool water every 15 minutes. Remember: Do not give liquids with
alcohol or caffeine in them, as they can make conditions worse.
- Heat Exhaustion - Remove the person from
the heat and into a cooler place. Remove or loosen tight clothing and
apply cool and wet cloths, such as towels or sheets. If the person is
conscious, give cool water to drink. Make sure the person drinks slowly.
- Heat Stroke - Life Threatening situation.
Help is needed fast - Call 911. Move person to a cooler place. Quickly
cool the body. Immerse victim in a cool bath, or wrap wet sheets around
the body and fan it. If vomiting or change in level of consciousness is
presented, do not give any thing by mouth.
Heat Wave
Tips:
- If a heat wave is predicted or happening - slow down.
Avoid strenuous activity. If you have to do strenuous activity the
recommended hours are between 4 am and 7 am.
- Stay indoors as much as possible. If air conditioning
is not available, stay on the lowest floor, out of the sunshine. Remember
electric fans do not cool air, but they do help sweat evaporate which
cools your body.
- Wear lightweight, light colored clothing. Light colors
will reflect away some of the sun's energy.
- Drink plenty of water regularly and often, even if you
do not feel thirsty. Your body needs water to keep cool.
- Water is the safest liquid to drink during heat
emergencies. Avoid drinks with alcohol or caffeine in them. They can make
you feel good briefly, but make the heart's effects on your body worse.
This is especially true about beer, which actually dehydrates the body.
- Eat small meals and eat more often. Avoid foods that
are high in protein, which increase metabolic heat.
Suggestions
for Places to Go During a Heat Wave
- Local Mall
- Library
- Senior Citizen's Center
- A movie theater
- A restaurant
- A home of a friend or relative
REMEMBER:
Check on elderly friends and neighbors.
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