Weather experts say Taiwan and the Philippines have experienced fewer typhoons in recent years.The reduced storm activity may be be the result of higher water temperaturesand changes in upper-atmosphere winds.Taiwan, which sits in the western Pacific, normally gets hit hardby three to four typhoons each year between the months of June and October.Each storm can kill five to 10 people and can cause major damage.Taiwan's neighbor to the south, the Philippines, can get up to 20 typhoons per year.The storms bring winds strong enough to blow down trees, and rainfall that can quickly turn streets into rivers.They usually cause mass evacuations and widespread transportation problems.The systems are called cyclones and hurricanes in other parts of the world.For the past three years, Taiwan and the Philippines have missed their historical average typhoon counts.Weather officials say one of the main reasons for this is higher water temperaturesin the mid-Pacific, where such storms form.In addition, wind directions have changed in the upper-atmosphereand are blowing more typhoons to the north.Jason Nicholls is an international weather expert with U.S.-based forecasting company AccuWeather.Nicholls told VOA that weather officials have seen a general warming of watersin the Indian Ocean and in the Pacific in recent years.Nicholls added that ocean temperatures in the central and eastern Pacific Ocean have been warming up since 2017.He said this caused typhoons to form in areas to the north and east of Taiwan and the Philippines.Upper-atmosphere winds pushed the storms north.Most of this year's 21 typhoons in Asia moved north to reach Japan, South Korea and China.The most severe, Typhoon Hagibis, killed 80 people in eastern Japan earlier this month.Western Pacific waters have been somewhat cooler this year, Nicholls said.This means fewer storms have formed near the eastern coasts of Taiwan or the Philippines.Asia's deadliest storms each year often reach the Philippines,including 2013's super-typhoon that killed 6,340 people.So far this year, no major typhoons have hit the country.It has experienced weaker tropical storms, however.Chen Meng-shih is a forecaster with Taiwan's Central Weather Bureau.He told VOA more northward-moving typhoons are likely to continueas long as "Pacific Ocean high pressure is weak and higher north."Many scientists have blamed rising ocean temperatures in the Pacific and Atlanticon a combination of natural conditions and man-made climate change.Man-made causes include the burning of coal, oil and gas.