For the past one week, if you are in Nigeria you would notice hot, uncomfortable weather which it is impossible to combat with an electric fan. The electric fans merely circulate hot air. The only relief could be gotten via an airconditioned environment. When we step out of such an environment, our bodies are pummeled by air so hot it is almost scalding. The scorching temperature ranges between 36-degree Celsius and 39-degree Celsius.
[Image is Free for Use]Source
This abnormally high temperature for a place that is used to high temperature is known as a heatwave.
Defining a heatwave is a bit difficult as there is no specific threshold of temperature for everyone that when temperature crosses, that is said to be a heatwave.
But if a temperature of an environment is 5 degrees above the maximum average temperature for the location, in 4 or more days in a row, it is called a heatwave.
So if 31-degree Celcius is the maximum normal temperature for a place and you suddenly have 36 or 37-degree Celcius temperature for 4 or 5 days in a row, the area is experiencing a heatwave.
Some other definition is that it is a when the temperature exceeds the top temperature of the location by 10% for a consecutive three days or more.
[A Screenshot of Temperature of Two Cities in Nigeria. Date 6th Feb 2018. Time: 3PM Local Time]Weather.com
One thing is similar in all the definition; there is a high temperature that exceeds the maximum temperature of a location for consecutive period of days.
The Dangerous High Temperature
The body operates at a normal temperature of 37-degree Celcius or 98.6 degrees Fahrenheit. In the event of it being subjected to a temperature 1 degree higher than this normal operating temperature over a period of several hours, heat exhaustion set in which may lead to hyperthermia. Hyperthermia is when the body temperature is higher than normal. The opposite of it is when it is too low which is called hypothermia.
The body regulates its temperature by sweating when you are hot; the subsequent evaporation cools the body. When the cold sets in, there is usually some shivering and shaking to make the blood flow and create heat in the process.
When the body temperature exceeds 42-degree Celcius, a phenomenon known as heat stroke occurs with the likelihood of death happening in a few hours.
How it Occurs
The heat waves occur when high pressure directs the air downwards thereby preventing the air near the ground from moving upwards.
[Wikipedia]Source: Heat wave
The warm air downwards is trapped; with its way of rising upwards blocked. The evaporation which could have taken place bringing a cooling effect can no longer take place.
Remember when evaporation occurs it takes away heat with it. This combines with the trapped air and makes it hotter.
Heat Waves Impact
Aside from the heat stroke which may lead to hyperthermia, there are other impacts heat waves may bring to the people.
The impact of a heatwave is dependent on its level of severity.
There are low, severe, and extreme heatwaves.
The low heatwaves affect mostly the babies and the elderly, while the severe heatwaves affect the adults irrespective of health status. The extreme is what affects the infrastructures such as the transportation, the power companies in the areas of generation, transmission, distribution and consumption.
Due to the heat, the electricity demand increases as more people run airconditioner at their homes. That usually overloads the system leading to blowouts or brownouts with resulting blackouts for some extended periods of time. The fuses on sensing this dangerous load demands fail, throwing the area it is protecting in a blackout.
In the area of transport, the roads under the extreme temperature may crack, shatter or be deformed as the road surface expands. Concrete roads are more at risk of breaking while asphalt may deform causing an uneven surface making for an unsafe driving condition.
The rail travel is usually the worst hit as continuous expansion of the metal due to high temperature may lead to a derailment. You can take a look here to see a severely warped rail track due to high temperature caused by heat waves here.
Even the air transport is not spared as planes lose lift during the take off as a result of heat waves. The heatwaves reduce the air density; takeoffs require longer runways to acquire enough lift in the less dense air.
How to survive a heat wave
In the absence of air conditioners, electric fans could do the trick.
[Maxpixel]Source
Though not as effective as an air conditioner. You can make yourself a homemade "air conditioner". Place a box fan behind a cooler of ice or ice in a bowl and sit in its path :)
Cross ventilation is required. Keep windows open.
Drink lots of water as one may easily get dehydrated in this situation. Foods such as caffeine and alcoholic beverages intake should be minimised as they aid dehydration.
But if it happens that your friend has an air conditioner, it is a great time to visit that friend :)
References
1.Wikipedia: Heatwaves
2.Reuters: Heatwaves Leaves Thousands of Australian Homes in Blackout
3.Extreme Temperature Effects on Transportation
4.Surviving a Heat Wave with no Airconditioner
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