Heat Waves

HEAT WAVES

• Heat wave is defined as a period of excessively hot weather coupled with excessive humidity.
• A heat wave occurs when there are a number of consecutive days with high temperature that the body cannot tolerate
• A a result of heat wave animals and plants suffer from 'heat stress'.
• Human beings suffer from sunstroke, severe dehydration with vomiting, fever and ultimately die.
• Based on physical meteorological perspective, heat-wave events can be classified into 
• Dry heat wave
• Dry heat-waves are characterised by dry weather conditions with clear skies and large inputs of solar radiation
• Windy conditions can increase the heat stress
•  Dry heat waves usually occur where air is warmed adiabatically
• Moist heat waves
• They are characterized with  very warm, oppressive conditions throughout the day and night
• They normally occur under a cloud cover at night which prevents loss of accumulated heat during the day
• Such heat waves are a feature of mid-latitude temperate

• A heat wave is caused by a system of high atmospheric pressure
• In a high pressure system, air from upper levels of the atmosphere descends and rotates outward
• As it comes down, it becomes compressed, which increases the temperature

The following are the effects of a heat wave on the human body

1. Headaches
2. Muscular cramps
3. Swollen hands, feet and ankles
4. Appearance of heat rash on the skin
5. Unusual fatigue
6. General discomfort
7. Signs of dehydration like
1. Excessive thirst
2. Less frequency of urination
3. Dark urine
4. Dark skin
5. Rapid pulse and breathing

 Medical intervention is required in the following situations

1. Difficulty breathing
2. Convulsions
3. Deterioration of consciousness
1. Confusion
2. Unusual behaviour
3. Agitation
4. Hallucination
5. Lack of response to external stimuli
4. Loss of consciousness

Heat stroke is the most serious effect of heat. It can occur suddenly and quickly leas to death if not treated quickly. Signs of heat stroke are

1. Oral temperature more than 39.5 C and rectal temperature more than 40 C
2. Dry skin, hot and red 
3. Dizziness and vertigo
4. Confused and illogical speech
5. Aggressive or strange behaviour 
6. General discomfort