The true story behind the film Sanctum
Many cave diving films have come out of Hollywood, some more painful to watch than others for those who understand the business.  The latest one, which is about to appear on our home town screens is, ‘Sanctum.’  This film got my attention, but only because it is based on a story that took place during an expedition that Rob Palmer, my late husband was on many years ago.  The expedition  was headed up by Andrew Wright and took place in the Australian outback known as the Nullarbar where this Pannikin Plains cave is located..
Left to right: Captain James Daly, Andrew Wright, and Stephanie Schwabe
This area is located just north of South Bight. (Photo and Map below).  Now imagine if you will, looking at the picture below of the desert and imagine that there is a massive cave system below all this clay and sand; a system  that is filled with water.  The hole in the middle of the photograph below is the entrance to the system.  Not as inspiring as the one we see in the film but it will do.
Map showing you the coast of South Bight.  The smaller scaled map below in this photo above with the black box shows the location of the dive site.  Note in the picture to the left the limestone layer.  This is where the cave formed.
It eventually came to the dive which I understood was spectacular.  The waters in this system are extremely clear, very much like in the Bahamas.   As for the dive, there was no problem.  No one had any serous issues with equipment or the dive.  Well as all cave diving adventures go, when you hit thirds (third of your air supply) you have to turn around and head back out of the cave system back to the wonderful yellow light that is our sun.
Arial view of the opening to the Pannikin Plans cave system.  In the film you see a very green entrance.  That site is in New Zealand.
So basically, the story starts of at the site with Rob talking to the village elder, an Aboriginal man who was the leader of the a tribe that actually owned the land.    The elder told Rob as he was standing next to the opening that, ‘today was not a good day to dive.’  Rob looked at him, looked at the stunning blue, cloudless sky above, looked back at him and asked, ‘why?’  The elder explained that he had observed some small animals leaving the entrance, indicating that something was going to happen today and it was not good.  Respectfully Rob thanked him and everyone continued with the days plans.    The floor of the opening is some 300 feet below the surface.  Dropping your equipment down was not an option and being that there was so much equipment to be lowered, special rigs had to be set up, some attached to motor vehicles, especially the really heavy stuff.  Needless to say, getting ready to dive at this site was a labour intensive exercise.  This system is very extensive, requiring a large number of scuba bottles  and for those few lucky ones that had scooters, that equipment needed to be lowered as well, carefully.  
A whopping 650 lbs!
Underground at the waters edge
Looking out of the cave entrance
Two scooters waiting to be lowered into the cave.
What is so interesting is that the storm nearly stopped over the entrance.  One might ask why?  There is actually an explanation and it has to do with pressure changes between the surface and the airspace underground.  However the most interesting part of this story is, why did the elder know that this event was going to happen.  Pressure changes are noted by most creatures that live in the ground.  So already at the beginning of the day, small changes, so small that we as humans were clueless, were occurring.  It’s about the same as when other mammals begin to act strangely before an earthquake.  As per the elder, living outdoors most of your life, one tends to pay more attention because it may become necessary to save your life.  As history is past on verbally amongst these people, he had probably learned that creatures leaving the safely and moisture of the underground to seek shelter in the hot surface life is not normal.  The changes that they sense must have indicated danger.  However, more interesting is later, about four years ago, a group of divers returned to the site and sometime in this event, soil samples were collected and examined.  What was determined was that these storm events were not freaks of nature but a regular event.  What was freakish was that there happened to be an expedition going on at the wrong time.
So as Rob tells the story,  everyone made it back to the waters edge and was beginning to climb out of the water.  Meanwhile, on the surface, mother natures had some other plans in mind and the words of the elder were beginning to ring true.  Something not so good was going to happen today and the event was nearly upon them.  What was being observed on the surface was a massive lenticular cloud screaming across the desert, heading to their exact location.  This cyclonic storm  coming at you would have shaken up anyone standing there.
As stated in the newspaper article below, this storm was a freak of nature.  
A little down under humor
So, how did the story end?  Well, according to Rob, having a fair bit of climbing experience, he began to try to find a way out of the system by very carefully climbing up the, as he described, unstable debris flow.  It took many hours but eventually Rob found a stable route up and basically one by one, the individual cavers made their way to the surface.  All equipment  that was in the cave was abandon.  
Entrance collapsing with the threat of some of the cars and trucks making their way into the hole.