Updated 09/2022 by Paul Smith, K5PRS
“A heat advisory is a notice issued by the National Weather Service of the United States. Local offices often have their own criteria. High values of the heat index are caused by temperatures being significantly above normal and high humidities, and such high levels can pose a threat to human life through conditions such as heat stroke.” Ref: Wikipedia
Here in the Houston Gulf Coastal area we certainly are no strangers to rather extreme summertime conditions of high temperatures coupled with high humidity levels. Practicality dictates that we be aware of and take preparations to deal with these adverse weather conditions.
Sweating and evaporative cooling are the body’s mechanisms that help control summer’s high heat levels. Even dry, hot air can become a problem but as the air becomes moist due to the onset of high relative humidity, evaporation becomes inhibited and adequate cooling becomes even more of a challenge.
When we are unable to maintain proper body temperature, the symptoms of heat cramps, heat exhaustion and heatstroke begin to manifest themselves. To quantify values, the term ‘Heat Index‘ was developed. The Heat Index is derived from that combination of temperature and humidity that describes “how hot it feels” and the expected symptoms from that heat range. The ‘Heat Index’ value is calculated as if you are standing in a ventilated, shady place so the following table has to be evaluated based on conditions and duration.
Prolonged exposure to ‘Heat Indices’ indicated produce:
- 80 to 90 degrees F: Could lead to earlier than expected fatigue making you prone to accidents.
- 90 to 105 degrees F: Represents the possibility of heat cramps and heat exhaustion.
- 105 to 130 degrees F: Can lead to heat cramps and if conditions aren’t remedied to heat exhaustion and to a possible heatstroke is also possible.
- “Heatstroke is a life-threatening condition that happens when your body temperature rises above 104 degrees Fahrenheit (40 degrees Celsius). It’s usually the result of overexertion in hot, humid conditions. Symptoms can include confusion, seizures or loss of consciousness. Untreated, heatstroke can lead to organ failure, a coma or death.” Ref: Cleveland Clinic
- Greater than 130 degrees F: Can quickly become fatal if exposure persists without proper precautions.
To cope with reducing potential health related problems:
- If you plan to be outside, restrict strenuous physical activities to early morning or late evening hours.
- Wear lightweight loose fitting and light colored clothing.
- Wear a hat to shield yourself from the sun and use sunscreen to minimize the risk of sunburn.
- Your body may loose as much as one gallon of water per hour through perspiration and that also lowers your body’s electrolytes. Drink plenty of fluids to stay hydrated and take salt tablets or add electrolytes. This cannot be stressed enough…you will BE dehydrated before you FEEL thirsty! Watch your urine; OFTEN is good and ORANGE is bad.
- Avoid alcohol and caffeinated beverages as they will increase the rate of water loss body via the urinary system and reduce sweating thus increasing the risk of heat exhaustion or stroke.
- Spend as much time as possible in air conditioning, under the cooling effects of a fan or at least out of direct sunlight as much as possible.
- Children, the elderly and people with chronic ailments are most at risk during periods of extreme heat so tend to them first.
- Don’t forget your pets can succumb to the effects of excessive heat. Ensure that they have plenty of fresh drinking water and a shady place to keep their body temperatures down.
- Avoid leaving pets or children in automobiles as the interior temperatures may quickly climb to the 150 degree F range. Even a tent in the sun can get dangerously hot…a canopy, which can be fashioned from a tarp or a poncho, is a better option.
In summary, dress for the occasion, stay out of the hot sun, monitor your urine and drink LOTS of fluids with electrolytes.
That concludes tonight’s training. Are there any questions, comments or suggested additions to this material?
Thanks, this is (callsign) clear to net control.