Heat wave occurs when excessive heat and humidity presides over an area for a prolonged period. During heat wave temperature rises by at least 5°C or more above average for more than five consecutive days. In the last few decades due to climate changes and global warming, the frequency of heat waves have increased not only in the day time but also in the night. The night time heat wave causes extreme discomfort to elderly people. Research shows that heat waves have caused more deaths than other natural disasters like Hurricane or Cyclone. Beside, high humidity heat wave, the dry heat waves with low humidity during summer causes forest fires or wild fires.
Countries like China and UK suffered from extreme heat waves in July 2013 and Southwest USA was severely impacted by heat waves in the month of June 2013. All these countries experienced heat waves for about a week.
Cause of Heat Waves
Heat waves occur when an extra high pressure system appears in an area. It pulls air from the upper layers of the atmosphere to the ground, causing the air compression and increase in the ground air temperature. This system of high pressure bars other weather systems to enter the area. Wind is non-existent and even clouds cannot enter the area, as a result the high pressure system lasts for a longer period causing higher temperature. Thus, staying out for a longer period of time during heat waves can be deadly.
Effects of Heat Waves
The effect of heat waves on human health and agriculture is more dangerous than the impact of any other natural disaster. High heat wave with high humidity becomes unbearable for many. As per the American Metrological Society, on an average about 1000 people die every year due to heat waves. The common heat waves related problems noticed among people are heat rashes; heat edema, which results in swelling of hands, feet and ankles; heat strokes; dizziness; heat cramps; heat syncope, etc.
Beside these health issues, prolonged exposure to high temperature causes temperamental changes in human beings as well as animals. Both can become aggressive and violent. Other problems associated with prolonged dry heat waves are wild fires, forest fires, as well as drying of vegetation leading to drought. High temperature also increases the demand of power or energy. At times the demand is more than supply, which leads to power outages. Extreme heat can also damage pipelines, power lines, etc.
Precautionary Measures
The impact of heat waves on health can be reduced if some precautionary measures are taken. The first and foremost important measure a local authority or government needs to take is to warn the locals in advance, so that people can avoid going out during this period. Also, drinking a lot of fluid is the best way to maintain a normal body temperature during excessive heat and resultant sweating. In fact crops or agricultural lands need to be amply irrigated to avoid drying of vegetation. Wearing light cloths and sunscreens, staying in cool environment as much as possible, are some other steps, which can be taken to bear the heat waves.