El-Nino Southern Oscillation (ENSO)

The phenomenon is caused by prolonged difference in Pacific Ocean sea surface temperature. It can cause changes in air pressure and ultimately affect the weather as well. (Click here to learn more about ENSO). The result of ENSO in 1997 was drought throughout Southeast Asia (SEA) stretching all the way till November.

Below are 2 charts that show the reduction of rainfall in 1997

Chart extracted from: http://www.fao.org/docrep/004/w8458e/w8458e00.htm

With the reduced precipitation increasing the likelihood of natural fires occurring, and the routine practice of burning forest to clear vegetation, the 1997 Indonesia Forest Fire escalated into one of the biggest forest fires.