The disappearance of Thailand under several metres of water in the annual floods marks the end of the 2010-2011 caving season. Overall it has been a fairly quiet season without any major caving expeditions. However, much useful work has been done including the first cave dives in central Thailand and the exploration of two major caves in Chiang Mai and Nakhon Si Thammarat.
On 29th November 2010 Peter McCarthy failed to surface when cave diving in Tham Song Hong in Trang. Despite an extensive search, including a dive to -124 m by one rescuer, his body was not recovered. This is the only caving accident of which I am aware.
The caving season started started with Alex Fletcher's cave dives in Tham Yai Nam Nao Resurgence Cave in Phetchabun, Tham Nam Lei in Chaiyaphum and Tham Nam Tok in Phitsanulok between the 23rd and 28th November 2010. Apart from one dive in 1999 in a vauclusian resurgence in Chaiyaphum these are the first recorded cave dives in this region of Thailand. In Tham Nam Lei the way on could not be found in the upstream sump, while in Tham Nam Tok there wasn't a sump and the way on was a duck. In Tham Yai Nam Nao Resurgence Cave the upstream sump was passed to a section of streamway leading to a second sump.
From the 12th December 2010 to the 21st January Thierry Tournier toured extensively throughout the country and visited caves in Chiang Mai, Chiang Rai, lamphun, Prachuap Khiri Khan and Phang Nga.
In February 2011 John Dunkley toured Isaan investigating sandstone caves including the long Tham Din Phiang in Nong Khai and the caves in the Phu Hin Rongkhla National Park. He then headed up to Mae Hong Song for a nostalgic return to Tham Nam Lang in the company of John Spies and Terry Bolger.
On a weekend trip from Bangkok (11th to 14th March) Jake Brodie-Stedman and friends visited Tham Pha Phueng in Nan, including descending the 127 m deep Fitch Pitch. Due to the limited time available this was a tourist trip and no exploration was carried out.
Krabi was visited by a group from the Shepton Mallet Caving Club from the 12th to 26th March 2011 (Ivan Hollis, Paul & Tiggy Dummer). Despite the very wet weather they managed to explore the upper series in Tham Khlang and visit the entrance to Tham Thewada.
The Chiang Mai Rock Climbing Adventures team had their annual visit to Doi Ang Khang in Chiang Mai between the 6th and 10th April 2011. A lot of effort was spent looking for the entrance to Ma Phong Sui Tung, but the cave could not be found (it is thought that the cliff has collapsed since the cave was discovered in 1984). As a consolation they did discover a major new cave which was explored to an estimated -200 m and which had a large river passage.
After an expedition to Laos a 2 man Shepton Mallet Caving Club team (Phil Collett and Martin Ellis) continued the resurvey of Tham Yai Nam Nao in Phetchabun from the 10th to 18th April 2011. Some other small caves were also surveyed in Phetchabun and Loei.
In Nakhon Si Thammarat Page Ashwell explored and surveyed Tham Pha Sri Thamma Sokarat between June and September 2011, taking length of this cave to over 2 km. Page also explored various other caves in this area.
In July 2011 Martin Ellis explored four small caves in Phetchaburi and Prachuap Khiri Khan.
A new book, "The Geology of Thailand" edited by M.F. Ridd, A.J. Barber and M.J. Crow was published by the Geological Society, Bath. ISBN 978-1-86239-322-6 in July 2011.
Three new volumes in The Caves of Thailand series were published in 2011. These were Volume 5: Chiang Mai, Volume 6: Nan & Phrae and Volume 7: Phetchabun.
The outlook for the 2011-2012 season appears to be quiet as regards to expeditions. I am only aware of two planned expeditons: Alex Fletcher will return to Tham Yai Nam Nao Resurgence Cave in November 2011 while the Shepton Mallet Caving Club are planning a third major expedition to Ban Mani Phruk in Nan in February 2012.