13 December 2010
Flooding, Landslides remains a risk in southeast Asia
By Eric Wolvovsky @ 5:16 PM
This season continues to be a wet one for southeast Asia. This is to be expected to be a season-long problem, but not an "all the time and everywhere" kind of event. Currently, there is a mix of anomalies in the region, with some very large precipitation surpluses on the Indonesian island of Java and on the Indonesian portion of Borneo. Southern Thailand and on the smaller islands in the Philippines have reported flooding and landslides respectively. Contrasting sharply with these wet conditions is Sumatra in Indonesia and Malaysia (both mainland and on Borneo). Over the course of the season these wet and dry areas will likely change places. The end result should be that a few locations have season long flooding. Some isolated locations, many of which will be too small to remotely monitor, will end up with heavy rain event, after heavy rain event all season long. At the same time there may be a couple areas that experience season long dryness, although this is much less likely. Flooding and landslides will be the main concern for the remainder of the season.
What is causing this is a byproduct of the current La Niña. Frequently with cold water in the equatorial Pacific, waters around southeast Asia turn warmer. This helps to encourage region wide heavy precipitation. There are some early indications that La Niña is starting to break down. This process, if it is indeed happening, will take several months before we start seeing changes in the atmosphere. Sometime in March-April-May would be the beginning of the change.