Heat Wave 22/05/2019 – Posted in: Daily News – Tags: AWARE, Heat wave, IMD
HEAT WAVE
For: Preliminary
Topic covers: Heatwave, Causes, Heatwave declaration criteria, Impact
News Flash
Andhra Pradesh Weather Forecasting & Early Disaster Warning (AWARE) centre of the Real-Time Governance Society has issued a five-day heatwave warning between May 25 and 29 when temperatures would be between 45° Celsius and 48° Celsius in various districts.
Heat Wave
According to IMD, Heat wave is considered if maximum temperature of a station reaches at least 40°C or more for Plains, 37°C or more for coastal stations and at least 30°C or more for Hilly regions.
Criteria used to declare heat wave:
(a) Based on Departure from Normal
- Heat Wave: Departure from normal is 4.5°C to 6.4°C
- Severe Heat Wave: Departure from normal is >6.4°C
(b) Based on Actual Maximum Temperature (for plains only)
- Heat Wave: When actual maximum temperature ≥ 45°C
- Severe Heat Wave: When actual maximum temperature ≥47°C
To declare heat wave, the above criteria should be met at least in 2 stations in a Meteorological sub-division for at least two consecutive days and it will be declared on the second day.
| Between 1900 and 2017, India’s mean temperature increased by more than 0.5 degree Celsius. (Lancet report – 2017) |
Heat Wave
Impacts of Heat Waves
(i) Socio-economic
- A decrease in labour output.
- Promote the spread of diseases like cholera and dengue fever.
- IPCC warned if the global communities are not to limit a temperature rise to 1.5 degrees, climate related risks to livelihoods, food, security, health, water supply and human security will further intensify.
(ii) Health
- The health impacts of Heat Waves typically involve dehydration, heat cramps, heat exhaustion and/or heat stroke.
The signs and symptoms are as follows:
- Heat Cramps: Ederna (swelling) and Syncope (Fainting) generally accompanied by fever below 39*C i.e.102*F.
- Heat Exhaustion: Fatigue, weakness, dizziness, headache, nausea, vomiting, muscle cramps and sweating.
- Heat Stoke: Body temperatures of 40*C i.e. 104*F or more along with delirium, seizures or coma. This is a potential fatal condition
What causes a heat wave?
A heat wave occurs when a system of high atmospheric pressure moves into an area. In such a high-pressure system, air from upper levels of our atmosphere is pulled toward the ground, where it becomes compressed and increases in temperature. This high concentration of pressure makes it difficult for other weather systems to move into the area, which is why a heat wave can last for several days.
Concerns
Higher daily peak temperatures and longer, more intense heat waves are becomingly increasingly frequent globally due to climate change.
India too is feeling the impact of climate change in terms of increased instances of heat waves which are more intense in nature with each passing year, and have a devastating impact on human health.
Source: The Hindu
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