This Day In Weather History is a daily podcast by Chris Mei from The Weather Network, featuring stories about people, communities and events and how weather impacted them.
In December 2017, southern Thailand faced a lot of rain. A lot more rain than capacity would allow. The area flooded for more than 30 days, which cost around 120 billion baht or US$4 billion.
Accumulated precipitation over Thailand from Dec. 1-7, 2016. (JAXA Global Satellite Mapping of Precipitation)
From Dec. 4-5, the province's 134 mm of rain accumulated in Songkhla and 120 mm in Nakhon Si Thammarat.
This was already after four days of extreme rain for other provinces in southern Thailand.
The Thai Meteorological Department's Automatic Weather Station reported that over 500 mm of rain fell between Dec.1-7 along the southern coast of the country.
Flooding on the streets of Koh Samui. (YouTube/Number12)
The reason the area was inundated with so much rain was due to multiple factors. During the end of November there's an intensifying convective activity that occurs from the South China Sea to the Malay Peninsula.
A La Nina event occurred, which resulted in high sea-surface temperatures, which is a perfect condition for cumulonimbus clouds to develop.
Cumulonimbus clouds are those big spanning clouds that pack a lot of rain and thunderstorm activity. Some roaring clouds that developed in the Gulf of Thailand passed over southern Thailand on Dec. 1 and 2.
On Dec. 3, a tropical depression developed just west of Malay Peninsula. A northeast monsoon was feeding the tropical depression extremely moist air, which resulted in record-setting, week-long rain.
Floods hits Thai Island of Koh Samui. (Instagram/@hannakarlson)
The flooding killed 91 people and affected 360,000.
The floods also wounded Thailand's economy. To hear more about the impact of the 2016-2017 Thai floods, listen to today's episode of "This Day In Weather History."
Thumbnail courtesy: Storyful