Haiyan may be strongest ever to hit land so far but as the oceans warm the power of storms is rising
When typhoon Haiyan - known in the Philippines as Yolanda - pounded into the islands of Samar and Leyte at 4.40am after picking up speed on a 900-mile track across the Pacific, the US navy's warning centre, JTWC, in Honolulu, calculated its winds to be gusting at up to 235mph (380kph).
This would make it the fourth most intense tropical cyclone ever recorded and possibly the strongest to have ever hit land. By comparison, St Jude, the storm that hit in southern England last month, had winds gusting to 99mph.
As Filipino communities calculated the flood and wind damage done in the 25-mile-wide path of the storm, meteorologists questioned claims that Haiyan was the strongest ever to make landfall. "All we can say at this stage is maybe. The estimates of wind strength and central pressure are just that – estimates – albeit from well-attested satellite techniques developed over decades. Without ground observations right in the centre of the track we can never be totally sure," said Julian Heming, tropical prediction scientist at the Met Office.
Haiyan is the third Category 5 "super typhoon" to hit the Philippines since 2010. "In 2010 Megi peaked at 180mph winds but killed only 35 people, and did $276m in damage. But Bopha, which hit the southern Philippine island of Mindanao on 3 December, 2012 , left 1,901 people dead and was the costliest natural disaster in Philippines history at the time," said Jeff Masters, director of meteorology at US-based Weather Underground in his daily blog.
According to the Philippine government, the area's typhoons have been getting stronger. "Menacingly, the Filipino typhoons are getting stronger and stronger, especially since the 90s," said Romulo Virola, head of the government's national statistics board. "From 1947 to 1960, the strongest typhoon to hit us was Amy in December 1951 with a highest wind speed recorded at 240kph in Cebu. From 1961 to 1980, Sening was the record holder with a highest wind speed of 275kph in October 1970. During the next 20 years, the highest wind speed was recorded by Anding and Rosing at 260kph. In the current millennium, the highest wind speed has soared to 320kph recorded by Reming in Nov-Dec 2006. If this is due to climate change, we better be prepared for even stronger ones in the future."
The steady warming of the oceans is likely to lead to fewer but stronger tropical typhoons, said scientists from the intergovernmental panel on climate change in a special report on climate extremes this year. "The average tropical cyclone maximum wind speed is likely to increase, but the global frequency of tropical cyclones is likely to decrease or remain unchanged," it said.
A record seven typhoons developed across the west Pacific during October, beating beat the previous record of six in 1989. Nearly one-third of the world's tropical storms form within the western Pacific and many track due west to the Philippines archipelago, the first major landmass they meet. In a normal season, only three or four typhoons develop.
Other regions are also experiencing some of their strongest storms in years. Last month, cyclone Phailin, which gusted at up to 160mph (260kph) forced 500,000 people in Orissa and Andhra Pradesh states, India, to flee their homes. The Atlantic hurricane season has been one of the quietest on record in 2013 but in September hurricane Manuel was one of the worst in Mexico's history, causing $4bn worth of damage.
Earlier this year the World Meteorological Organisation calculated that tropical cyclones had killed nearly 170,000 people in 2000-2010, and affected more than 250 million, causing economic damage of $380bn.
After roaring across the Philippines, typhoon Haiyan is expected to move into the South China Sea and eventually hit Vietnam and Laos. "Once Haiyan exits into the South China Sea, it will steadily decay, due to colder waters and higher wind shear. However, it will still be a formidable Category 1 or 2 typhoon when it hits Vietnam and Laos, and I expect that the 12 or more inches of rain that the storm will dump on those nations will make it a top-five most expensive natural disaster in their history," said Masters.
[Image via Agence France-Presse]