heatwaves and mitigation.pdf

1. Heat waves
Kanza Saleem
&
Amna Rustam

2. Contents
 Introduction
 Types of heat waves
 Mechanism of heat waves
 Effects on human beings
 Case study on Karachi
 Causes of Karachi heat-waves
 Heat waves disasters in history
 Impacts of heat waves

3. Introduction
 It is a prolonged period of excessive heat, often
accompanied by excessive humidity.
 Heat waves occurs when there are a number of
consecutive days with above average temperature, that
the body can not tolerate.
 As temperature rises people animals and plants suffer
from heat stress.

4.  Apart from death more and more people also suffers
from sunstroke, severe dehydration, with vomiting and
high fever.
 And cause disruption to community infrastructure like
power supply, public transport and services. Also known as
“Silent Disaster”.
 The condition become more severe in May and June in
Pakistan.
Cont..

5. Categorization
Based on a physical meteorological perspective, heat-wave
events can be categorized into two broader types:

6.  Dry heat-waves
Characterized by dry weather conditions with clear skies
and large inputs of solar radiation.
Accompanied by windy conditions, which can increase heat
stress.
Dry heat waves usually occur in locations with a
continental or Mediterranean climate or where air is
warmed adiabatically.

7.  Moist heat-waves
Characterized by very warm, oppressive, humid
conditions throughout the day and night.
Often with nocturnal cloud cover, a feature that
prevents loss of heat accumulated throughout the day
and thus provides little night-time relief.
Such heat wave often a feature of mid-latitude
temperate and maritime climates and may be endemic to
some regions.

8. Mechanism
 A heat wave is caused by a system of higher
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 temperature and dries it out.

9. Effect on human beings
o Heat stroke
o Dehydration
o Sun burn
o Air pollution
o Drowning

10. Karachi 2015 heat wave
 During summer season, Karachi has displayed very
high occasional day temperatures up to 44.8°C .
 With the heat index ranging between 58.3°C -66.1°C
 This severe heat wave event persisted for
consecutive 5-days from 19-23 June.
 Over 2500 innocent souls have lost their valuable
lives to the sweltering heat.

12. Causes of Karachi heat wave
Following are the causes of heat-wave event in Karachi.

13. Comparison showing urbanization in Karachi

14. Some miserable heat-wave
disasters in history
 Europe, 2003:
About 71,310 people died
 Russia, 2010:
About 55,736 people died
 Europe, 2006:
About 3,418 people died
 India, 1998:
About 2,541 people died
 Pakistan, 2015:
About 2500 people died

15. 

16. Impacts of heat-waves
o Stress for outdoor workers.

17. oStress in animals.

18. o Damage to crops and vegetation.

19. o Infrastructure stress i.e. buildings, roads, rail and
other infrastructure.

20. o Increased risks for sporting and outdoor recreation
activities.

21. Cont..
o Increased energy demand, e.g. greater demand for air
conditioning.
o Shifts in tourism preferences due to higher
temperatures.
o Human morbidity and mortality, particularly among the
elderly & infirm.