Typhoon Ketsana

Typhoon Ketsana, named Ondoy by PAGASA was a catastrophic tropical cyclone that caused extensive damages across Southeast Asia, particularly in the Philippines and Vietnam. It is both the second deadliest and costliest typhoon of the 2009 Pacific typhoon season, with at least $1.15 billion in damages and 710 fatalities, trailing behind Morakot with 789 deaths and damages worth $6.2 billion.

The sixteenth tropical storm and eighth typhoon of the season, Ketsana formed early about 860 km (530 mi) northwest of Palau on September 23, 2009. Initially, it was downgraded to a low pressure area by the Japan Meteorological Agency (JMA), but after drifting through favorable conditions, it intensified the next day and was categorized as a tropical depression by the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), and was given the name Ondoy after entering the Philippine Area of Responsibility. The Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert on the depression. It was then upgraded to a tropical depression by the JMA later that morning before the JTWC followed suit early on September 25, designating the depression as 17W. Soon, the depression strengthened into a tropical storm, and was given the name Ketsana by the JMA. Shortly after, it made landfall over the Philippines, and as it moved into the South China Sea, the storm intensified while moving towards the west. It peaked as a Category 2-equivalent typhoon before ultimately making landfall on Vietnam at peak intensity on September 29, dissipating on the next day.

While Ketsana made landfall north of Metro Manila as a tropical storm, it enhanced the southwest monsoon, bringing record-breaking rainfall and flooding across the Philippines' capital. At least 464 deaths and $237 million (₱11.1 billion) were attributed to the typhoon, making it the most devastating tropical cyclone to hit Metro Manila, surpassing Typhoon Patsy (Yoling) in 1970. Flood water levels also reached a record 20 feet (6.1 m) in rural areas. In response to this, President Gloria Macapagal Arroyo declared a "state of calamity" encompassing most of Luzon after at least 86 people were initially reported dead in landslides and other incidents. Recovery efforts from the storm's onslaught would later be hampered by Typhoon Parma, which made landfall in the Philippines roughly a week after Ketsana.