During that time, the Northern Hemisphere, which includes Pakistan was experiencing summer while the Southern Hemisphere was experiencing winter.
The air over Pakistan heats up due to the higher temperature, creating an area of low pressure, while the air over the southern hemisphere cools down due to the lower temperature, creating an area of high pressure. The air from the southern hemisphere then moved towards the northern hemisphere due to the pressure difference, picking up moisture as it travels across the Indian ocean until it reaches Pakistan, bringing heavy rains and therefore causing the floods.
Drainage Basin
As you can see on the map on the bottom left, Pakistan on the low lands around the Indus River. So when it started raining in the area, all of the rainwater flowed into the Drainage basin which is Pakistan. This was made worse when the River overflowed and flowed down to the low lands of the Sindh Province.
You can also see from the diagram on the right that the relatively higher lands of Balochistan and Punjab are not as badly affected as the Sindh Province.
La Nina
Another probable cause of the floods was La Nina, which is characterized by abnormally cold temperatures in the Equatorial Pacific. This resulted in abnormal temperature and pressure conditions which may have lead to the disastrous monsoon rains.
Causes of 2010 Pakistan Floods
South East Monsoon
During that time, the Northern Hemisphere, which includes Pakistan was experiencing summer while the Southern Hemisphere was experiencing winter.
The air over Pakistan heats up due to the higher temperature, creating an area of low pressure, while the air over the southern hemisphere cools down due to the lower temperature, creating an area of high pressure. The air from the southern hemisphere then moved towards the northern hemisphere due to the pressure difference, picking up moisture as it travels across the Indian ocean until it reaches Pakistan, bringing heavy rains and therefore causing the floods.
Drainage Basin
As you can see on the map on the bottom left, Pakistan on the low lands around the Indus River. So when it started raining in the area, all of the rainwater flowed into the Drainage basin which is Pakistan. This was made worse when the River overflowed and flowed down to the low lands of the Sindh Province.
You can also see from the diagram on the right that the relatively higher lands of Balochistan and Punjab are not as badly affected as the Sindh Province.
La Nina
Another probable cause of the floods was La Nina, which is characterized by abnormally cold temperatures in the Equatorial Pacific. This resulted in abnormal temperature and pressure conditions which may have lead to the disastrous monsoon rains.