( CNN ) -- With all of the recent deadly storms in the news , it may seem has though this year as been more active than a normal year . Since September 1 we have seen eight tropical cyclones , five of which became typhoons , two reaching Super Typhoon status , the strongest classification of tropical cyclones in the Western Pacific . A Philippines scientist points to a screen monitoring Tropical Storm Parma and Typhoon Melor . But when we look at the numbers , 2009 has actually been slightly below average . So far we have seen 19 tropical storms in the Western Pacific , which is slightly behind the pace needed to reach the yearly average of 27 . Named storms , however , are a notoriously poor metric for measuring the ferocity of tropical seasons . Take this year in the North Atlantic for instance . Yesterday , Tropical Storm Henri became the eighth named storm , coming only a week after the National Hurricane Center would normally name the eighth storm on an average year . So while 2009 may contain an average number of storms , no one will argue that 2009 has so far been a dud of a hurricane season in the Atlantic . This is largely due to the fact a majority of the storms so far this season have been weak , short-lived , and not made landfall ( Tropical Storm Grace did not even last one day ) . A better way to measure hurricane and typhoon seasons is with Accumulated Cyclone Energy ( ACE ) , a surprisingly simple mathematic calculation . The National Oceanic and Atmospheric Administration , a U.S. scientific agency that studies oceans and the atmosphere , uses ACE to approximate the energy contained in each cyclone . ACE is continuously monitored all around the globe by Ryan Maue , a doctoral student at Florida State University , and according to Maue 's numbers the West Pacific is 20 percent below average for the season . For comparison , the North Atlantic is 50 percent below average for the year . Go here to see Maue 's research . Despite the fact that 2009 has been below average for the season , the past month has been remarkable , with five of the eight storms making direct landfall in Asia . Typhoon Melor made landfall in central Japan early Thursday . In the Philippines , people are still recovering after two typhoons hit the nation in less than two weeks . Typhoon Parma made landfall last weekend , killing at least 16 . Filipinos were still recovering from Typhoon Ketsana , which hit the country in late September . Hundreds of people were killed from that storm , primarily in the Philippines and Vietnam . Earlier in the summer , more than 600 people died in Taiwan after Typhoon Morakot struck in August . Also in August , Typhoon Etau killed more than a dozen in Taiwan after it brought flash floods and landslides . What is behind this recent uptick in activity and why are all the storms seemingly coming at once , and late in the season ? The answer may be El Nino , which refers to a periodic change in the atmosphere and ocean in the Pacific . During El Nino , the waters in the central and eastern Pacific are warmer than normal , and the effects on global weather can be drastic and far-reaching . According to Maue , we see more cyclones later in the season during El Nino years in the Western Pacific , and they tend to form farther east . With the warmer sea surface temperatures during an El Nino event , this would allow these storms more time over open water to grow into large and powerful typhoons . In fact , we tend to see more `` Super Typhoons '' during El Nino years , and this is true again this year , as Choi-Wan and Melor both reached Super Typhoon status . El Nino also is a likely culprit for the inactivity in the North Atlantic , since El Nino can cause more wind shear in the upper atmosphere , a condition that limits the ability of Tropical Cyclones to survive .
Spate of deadly storms have hit Western Pacific in 2009 . Statistics show number of storms in Asia-Pacific in recent weeks is below average . El Nino phenomenon likely culprit behind recent spate of East Asia storms .