How easily does Manila sink in flood waters?

Posted on Friday, 3 October 2014 3:02 pm

Last Wednesday's rains brought Manila to a standstill and the truth behind the sudden downpour is scary: it takes barely two hours of heavy rain for the Metro to sink in flood waters.

Since Ondoy hit in 2009, there have been many changes to how we forecast and warn about floods. However in two separate instances this year, Manila was over its head due to flood water.

Comparing average rainfall of these flood instances and PAGASA's rainfall advisory, it seems to be that either (1) we incorrectly forecast how much rain was going to fall or (2) the rainfall advisory is not at par to how deep we expect flooding to be. Barely two hours of moderate rain (7 mm/hour) on Oct. 1 and over 10 hours of heavy rain (10 mm/hour) on Sep. 19 caused widespread flooding. The Oct 1 thunderstorm dumped 14 mm of rain over the Metro while Sep 19 dumped 260 mm over 24 hours. Despite these serious problems systems will not in be place until March 2015 when some of the projects to alleviate flooding will be put into place.