The 10-km Tham Luang complex in Chiang Rai is relatively unexplored and includes narrow, dark passages
Rescuers in Thailand are deciding how they will rescue 12 boys and their soccer coach from a flooded cave complex as the country's north braces for more monsoon rains that could imperil the operation.
The boys are around four km (two and a half miles) from the cave's entrance, according to the Thai navy, and about 400 metres from Pattaya Beach, a large, elevated point inside the Tham Luang cave complex.
But before the group, trapped since June 23, can be reunited with their families, they will have to contend with debris clogging some of the passage ways back to the cave's entrance and high water levels that might require them to use scuba diving gear, despite no previous training.
Many have questioned how the children can be brought out if it took even expert divers nine days to reach them.
The 10-km Tham Luang complex in Chiang Rai is relatively unexplored and includes narrow, dark passages. Before the boys reach a T-junction three km north of the cave's entrance they will have to dive at least once, said rescue workers.
"It takes six hours to get to where the children are and five hours to come back [to the cave's entrance]," said Major General Chalongchai Chaiyakum, deputy commander of the Third Army Region.
Officials have said between two to three divers will accompany each member of the group.
Thailand is in the middle of its monsoon season which usually ends in mid-October. A sign outside the cave warns visitors it is prone to flooding.
Thomas Hester, detective superintendent with the Australian Federal Police Specialist Response Group, said there were "heavily flooded areas" inside the cave complex.
"Its very difficult to see, very difficult to move inside that flooding system," said Hester.
One major challenge will be a "crisis" point marked on the Thai Navy's map of the cave – an area where rescuers say the cave dips – and debris, mud and water pools, which require constant clearing.
The point is between Pattaya Beach, a few hundred metres from where the boys were found, and the T-junction, according to Thai divers assisting in the operation.
From the T-junction to the entrance of the cave water levels are currently "manageable", said Chiang Rai Governor Chiang Rai Governor Narongsak Osottanakorn.
The Thai Navy said water at the cave's entrance was 34 cm deep but levels can vary depending on the rain.
"From the T-junction to Pattaya Beach [there] is a slope and a passage about 15 metres long, a very narrow passage. Small people can push through but not large people. You have to go in one at a time. Those who are using an oxygen tank have to remove it push it forward.... After this point you come to a dry area," Chalermphon Hongyon, president of the Water Rescue Club Region 7, told reporters.
Rescuers are currently considering four options to extract the boys.
Plan A is to teach the boys, aged between 11 and 16, how to dive and to assess whether they are fit enough to tackle the journey out. Plan B is to pump and drain enough water out of the cave so that the group can crawl out part or most of the way.
Another is to find an alternative way into the cave through a natural shaft near the boys' location that can be drilled from above.
"We are searching for shafts, so maybe can adjust plans and go down and explore," Narongsak said on Thursday. He did not elaborate.
The last option, one that many say should be a last resort, is to keep the boys inside the cave with enough food and water until they are strong enough to leave or until water levels subside.
More rain is also expected over the weekend, according to Thailand's meteorological department, something that will likely force rescuers again to reassess their plans.