Questions about going into Thai cave during monsoon season

It was great news that the twelve boys from a soccer team and their coach were found alive deep inside a cave system in Thailand.

Guardian: Thailand cave rescue: where were the boys found and how can they be rescued?

When 12 missing Thai boys and their football coach were found alive deep in a cave system on Monday, joy was tempered with anxiety. The caves are flooded with surging monsoon waters, pitch black and in places too narrow to allow rescuers to pass while carrying scuba gear. None of the boys can swim or dive. The dilemma: risk a highly dangerous escape or wait possibly months for the waters to subside.

News.com.au: Next 24 hours will be crucial in Thai cave rescue drama

A CAVE explorer assisting Thai authorities trying to rescue 12 trapped schoolboys believes “we’ll know in the next 24 hours” if they will live or die.

British cave expert Vern Unsworth, who lives in Thailand, said the conditions were getting worse and there was now a narrow window in which the group could escape.

“I think we’ll know in the next 24 hours…We’ll keep our fingers crossed – everybody needs to pray and hope for a good outcome,” Mr Unsworth told the BBC.

The boys aged between 11 and 16, along with their football coach, have been trapped in the flooded Tham Luang cave system for 12 days.

But heavy monsoon rain is coming, and Mr Unsworth said rain that had already fallen had caused a dramatic rise in water levels in the cave.

Obviously the rescue is the most important thing right now.

But I have to ask why they were in the cave at all in the monsoon season, especially if it could take months for the rainy season to finish and for waters to subside.

Is the level of flooding unusual, even during the monsoon? Or is it a common risk?

Wikipedia says that the Thai monsoon runs from May to October, so flooding must have been a risk for some time.