Twin typhoons threaten western Pacific

As was widely predicted earlier this year, due to the developing El Nino this is turning into one of the most active Pacific typhoon seasons on record.

Taiwan is still recovering from the effects of Typhoon Soudelor which struck on August 11. Soudelor killed at least eight people, with four others still listed as missing. Sustained winds of up to 150km/h battered the island and 1,334mm of rain fell in the eastern Yilan County.

Now, Typhoon Goni is threatening to bring similar weather conditions to the country on Saturday. Goni has intensified into a Category 4 system (on the five-point Saffir-Simpson Scale) with sustained winds of 217km/h. Conditions for further development of Goni remain favourable, with low wind shear (change of wind direction with height) and high sea surface temperatures.

Goni is currently to the east of the Philippines and is expected to track towards the west before turning northwards. At that point the latest forecasts track Goni close to the east coast of Taiwan. The main concern is the very slow speed of the typhoon. This could allow Goni to drop vast amounts of rain across the country, leading to flash flooding and landslides.

A similar slow-moving typhoon hit Taiwan in August 2009. Typhoon Morakot is known to have killed almost 700 people after an incredible 2,777mm of rain fell on the island producing severe flash flooding and inducing massive landslides.

There is no suggestion at this stage that Goni will be anywhere near as severe, but it will need to be closely monitored in the next few days.

Another major typhoon, Atsani, lies in open water several hundred kilometres to the east of Guam. Atsani may well reach super typhoon status with winds of 260km/h in the coming days. It is expected to pass to the northeast of the island of Iwo Jima before making a right turn. The timing of this turn will be critical, as any delay could see it heading close enough to Japan to have a major effect on the weather along the eastern side of Honshu.