After five of seven people trapped in a flooded cave in Laos were found, footage showed one of the men putting his head in his hands in gratitude at his rescuer’s appearance after a week of uncertainty in the dark chamber.
The mission to find them was itself fraught, but so too will be the extraction.
Like the 2018 rescue of a boys football team in Thailand, the ecstasy of finding them alive was tempered by the fact that getting them out of the cave remained itself potentially life threatening.
“The job is not over yet. The next step is to find a way to mobilise the five people out of the cave. This isn’t easy,” Kengkard Bongkawong, head of operations for Metta Tham Rescue, a Thai rescue group, wrote on social media.
So what happens next?
Where were the five people found?
Teams battled for days to reach the terminal chamber, where the five people were found. Reaching the chamber required teams to crawl for hundreds of metres, and move through long stretches of dark, flooded areas inside the cave. Some of the tunnels are just 60cm wide.
The chamber is around 300 metres from the exit, Mikko Paasi, a Finnish diver who was part of the rescue mission said on social media.
“The environment is extremely remote and hostile that starts with four-kilometre jungle track to the site and when inside the mine you have to navigate hundreds of metres of constant restrictions, flood waters, collapse hazards and high risk of contaminated air quality,” Paasi wrote.
What are the conditions inside the cave?
Video footage shows dark, narrow passageways, parts of which were almost completely inundated by muddy waters.
Grant Pearce, the national director of the Cave Divers Association of Australia, described the rescuers’ attempts to find to their way to those trapped as “akin to going to visit somebody’s house that you haven’t been to before, all the lights are off and you need to find your way through the rooms without stubbing your toes.”
Cave divers have specialised training to navigate “sumps” – the term for passages which contain water – as well as managing conditions including varying tunnel and entrance sizes and low visibility. They also have specialised equipment including multiple torches that are extremely bright, but these can be useless when it’s a muddy environment as divers are working in zero visibility conditions, Pearce says.
That’s why divers run a fixed line from the surface all the way through the cave – like a long extension cord that divers hold on to, ensuring that even in zero-visibility conditions, there is a tactile reference to exit the cave or to reach where people might be trapped, “a bit like breadcrumbs,” Pearce says.
Low oxygen supplies, more rain and a lack of dive experience are among the factors that will make it difficult to get the trapped people out of the cave.
Kengkard has appealed for people to donate oxygen tanks, writing on social media: “We need to borrow as many oxygen tanks as possible and want to set up an oxygen refilling station in front of the cave.” He told the Guardian at least 30 tanks were needed, for use by both rescuers and the stranded men.
Kengkard, who helped in the dramatic rescue of a young Thai football team in 2018, is among international and Thai divers who travelled to Laos to help in the mission.
Outside of rescue missions, cave divers would generally follow the “thirds rule” when it comes to ensuring they take enough air with them – one third to use on the way in, one third on the way out and the last third typically for another person, typically if a buddy needs it, Pearce says. Unlike open-water diving, cave divers cannot make a direct ascent in an emergency.
Pearce says the people trapped likely do not have the skills and experience of cave divers, and so would have to be attached to the rescuer in some form or another. The state of the person being rescued may also be a factor. Iif they are anxious there is the added danger, he says, that “they’re always on the edge of potentially panicking and making life difficult for the rescuer and themselves.”
The rescue of 12 schoolboys from a flooded cave in Thailand in 2018 saw them sedated, equipped with full-face scuba masks and ferried underwater while tethered to a diver. Pearce says that although that rescue was successful, each rescue is unique in terms of the cave conditions and the people being rescued, so “that doesn’t mean that the same approach would be used.”