Typhoon Prapiroon (2006)

Typhoon Prapiroon, known in the Philippines as Tropical Storm Henry, was a minimal typhoon which caused deadly flooding in southern China in August 2006. Prapiroon developed out of a persistent area of convection accompanied by an area of low pressure on July 25 about 120 km (75 mi) west-southwest of Yap. Two days later, both the Japan Meteorological Agency (JMA) and PAGASA classified the system as a tropical depression, with PAGASA giving it the local name 'Henry'. By July 31, the Joint Typhoon Warning Center (JTWC) classified the system as Tropical Depression 07W. A strong subtropical ridge located to the north of the depression led to a west-northwest movement for most of the storm existence.

A few hours after the JTWC began issuing advisories, the depression made landfall in Dilasag, Philippines. The next day, after crossing into the South China Sea, the depression was upgraded to a tropical storm and named Prapiroon. Several hours later, PAGASA issued their final advisory on the storm as it moved out of their area of responsibility. By the morning of August 2, Prapiroon intensified into a typhoon and reached its peak intensity with winds of 120 km/h (75 mph 10-min). The typhoon maintained this intensity until shortly before landfall near Shangyang, China at 12:00  UTC on August 3, where it weakened to a severe tropical storm. Prapiroon quickly weakened and dissipated early on August 5.

Severe flooding in the Philippines and China from Prapiroon killed 94 people and left 10 others missing. Over 20 million people were affected by the storm in China alone. Significant flight delays and cancellations in Hong Kong led to $1.9 million in compensation pay to travelers. About 30,000 homes collapsed and 140,000 others were damaged by the storm. Damages were estimated at $640,000 (2006 USD) in the Philippines and $984 million (2006 USD) in China. The International Red Cross and Red Crescent Movement sought $4,825,791 (2006 USD) in funds for victims of the typhoon.

Meteorological history

On July 25, an area of convection persisted about 120 km (75 mi) west-southwest of Yap. Satellite imagery indicated that a low level circulation had developed and was under an area of light to moderate wind shear. The low traveled in a general northwest fashion as upper level outflow improved. By July 27, the low deteriorated, becoming elongated, and convection remained disorganized. However, as the low neared Central Luzon, Philippines, shower and thunderstorm activity near the center of the low increased, and based on its organization, the Japan Meteorological Agency (JMA) classified the system a tropical depression early that morning. Shortly after, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) designated the system as Tropical Depression Henry. As the depression neared the northern Philippines, wind shear increased, partially exposing the center of the system to the south. At 02:30  UTC on June 30, the Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert, and at 00:00 UTC the next morning, the JTWC classified the system as Tropical Depression 07W.

Upon first becoming a tropical cyclone, the depression tracked towards the west-northwest due to a strong subtropical ridge located to the north of the system. A few hours later, the system made landfall in Dilasag, Philippines with winds of 55 km/h (35 mph 1-minute winds). After being over land for most of July 31, the depression relocated into the South China Sea and the JTWC determined that it intensified into a tropical storm. At around 06:00 UTC, the JMA designated the storm Tropical Storm Prapiroon about 300 km (185 mi) northwest of Dagupan, Philippines, a few hours later, PAGASA issued their final advisory on Tropical Storm Henry (Prapiroon) as it moved out of their area of responsibility. Prapiroon gradually intensified as it moved towards the west-northwest at 24 km/h (15 mph), and by that afternoon, the system had completely moved into the South China Sea. By the nighttime hours, the JMA upgraded Prapiroon to a severe tropical storm, as they determined that the maximum sustained winds had reached 95 km/h (60 mph 10-minute winds). By the morning of August 2, the JTWC upgraded Prapiroon to a typhoon, and a few hours later, the JMA upgraded Prapiroon to a typhoon.

Heading towards the northwest, Prapiroon reached its peak intensity early on August 3. The JMA estimated that Prapiroon peaked with winds of 120 km/h (75 mph 10-minute winds) with a minimum pressure of 970 mbar (hPa; 28.64  inHg), while the JTWC estimated that the storm peaked with winds of 130 km/h (80 mph 1-minute winds). Prapiroon maintained this intensity for 12 hours before weakening slightly as it made landfall near Shangyang at 12:00 UTC. At the time of landfall, the JMA downgraded Prapiroon to a severe tropical storm, with winds of 110 km/h (70 mph 10-minute winds) while the JTWC analyzed Prapiroon to have had winds of 120 km/h (75 mph 1-minute winds). Due to the interaction with land, the storm quickly weakened. Early on August 5, both agencies issued their final advisories on Prapiroon as it dissipated over central Guangxi.

Preparations

Philippines

As Tropical Depression 07W, locally named 'Henry' by PAGASA, neared the provence the northern Philippines, a total of 17 provinces were placed under a storm alert as winds of 30 kts (55 km/h) were likely to affect areas near the depression. Residents in the northern Philippines were advised to avoid low-lying areas and be alert for flooding. About 15,000 people were evacuated following heavy rains from the outer bands