Heavy rains expected in Thailand are increasing the pressure to rescue 12 boys and their soccer coach who are trapped in a cave. The boys, aged 11 to 16 years old, have been trapped underground by floodwaters for 11 days and new flooding could make it harder to get them out or reach them with fresh supplies.

Anmar Mirza, coordinator of the National Cave Rescue Commission, has more than 30 years of experience in cave rescues. Mirza joined "CBS This Morning" from Indiana to discuss some of the rescue options being considered and the complications that could arise if the boys, who don't know how to swim, have to dive out themselves.

"Initially we were looking at three primary options of getting them out," he said. "The diving option, which has been discussed. The waiting for water to go down, for a lull in the rain, to allow them to pump it down enough for them to get out on their own. And then there was the potential for putting another entrance in, either by drilling or by finding and exploiting a natural entrance," he said.

According to Mirza, that last option of using a natural entrance is becoming less and less likely and instead officials are focusing on the first two. But if additional flooding threatens the area where the boys are currently sheltered, they may have no choice but to dive their way out – a feat for even the most experienced divers.

"It's a very difficult thing to plan for and be ready for all the contingencies. And the problem becomes is the contingencies are what can potentially be fatal. Panicking, losing your mask, having an issue with the equipment in an environment where you're enclosed is incredibly dangerous," Mirza said. "If the flooding situation worsens to the point where they decide that they need to try to do something, they're going to have to weigh the risk versus the potential benefit there, and regardless of which option is used, whether it's diving or waiting for the water to go down, there are risks involved. There are no good choices."

While the biggest immediate risk is more flooding, there are also risks associated with waiting for the floodwaters to recede, which could take months.

"The other long-term risks, of course, are the issues that they may have medical issues, they may have psychological issues. Those are more manageable and they don't affect the group as a whole, in general," Mirza said.

As CBS News' Ben Tracy reports, officials say is still too dangerous to carry out a rescue mission but they are trying to install a phone line so the children can talk to their parents. Newly-released videos appear to show the boys in good spirits, smiling as they interact with divers and medics.

The provincial governor said the boys have been practicing wearing diving masks and breathing, but does not believe they have attempted any practice dives.