The aftermath of Super Typhoon Haiyan

Monday 18th Nov 2013 by theWeather Club

Super Typhoon Haiyan has been in the worldwide news since Friday 8th November, when the typhoon made landfall in the Philippines. In the north-west Pacific a tropical cyclone is classified as a Super Typhoon when its winds are greater than 150 mph. The strongest reported wind speeds associated with Haiyan reached 195 mph, and if verified this would make Haiyan the strongest tropical cyclone to make  landfall on record and the fourth most intense tropical cyclone ever observed.  

It has been a very active typhoon season in the Pacific with Typhoon Haiyan being the Philippines' 25th typhoon this year. Most tropical cyclones in the Northern Hemisphere typically develop between May and October, when the water temperatures in the subtropics are highest. This year, tropical cyclone activity in the Western Pacific increased in October and continued into November, due to very warm sea surface temperatures (reaching 30℃ ) and low vertical wind shear (difference in wind speed and wind direction with height), which both sustain a cyclone’s development.

The Philippine archipelago comprises over 7,000 islands. Haiyan caused catastrophic destruction in the central area, particularly on Samar Island and Leyte. According to the UN, about 11 million people have been affected. They are in a desperate situation, without water, food and shelter. A huge international relief effort is underway, but rescue workers have struggled to reach some remote towns and villages cut off since the storm. An official death toll is yet unknown, but figures as high as 10,000 have been mentioned in the media.

Questions are being asked whether Super Typhoon Haiyan was caused by climate change. While it is not scientifically possible to attribute one particular event to climate change, some are wondering if we should expect more such strong storms in the future. On the 11th November the UN Climate Change Conference commenced talks in Warsaw, at which a delegate from the Philippines Yeb Sano said: "Science tells us that simply, climate change will mean more intense tropical storms. As the Earth warms up, that would include the oceans. The energy that is stored in the waters off the Philippines will increase the intensity of typhoons and the trend we now see is that more destructive storms will be the new norm“.

On the other hand, the most recent report from the Intergovernmental Panel on Climate Change (IPCC), released in September, found that there was “low confidence in attribution of changes in tropical cyclone activity to human influence”. The report also stated with “low confidence” that the number of intense tropical cyclones will increase over the next few decades.

Natural disasters are not uncommon in the Philippines and the local people are resilient, but the scale of damage caused by Super Typhoon Haiyan is unprecedented. The strength of Haiyan lessened as it moved towards the South China Sea. By the time Haiyan made landfall in North Vietnam, on Monday last week, it had been downgraded to a tropical storm (with 1 minute sustained winds of 44–62 mph). Almost 1 million people were evacuated and hopefully the aftermath of Haiyan will be much less severe than in the Philippines.