Case study: good organization as a guarantee for security


Cave exploration carries risks. Deep abysses, waterfalls, climbing, rivers, narrow passages, blocked halls, kilometers of underground galleries hours and days away from the surface… the list is not exhaustive. On top of that, we have to consider the explorer’s personal, subjective judgment, knowledge, skills, experience, and understanding of risk. Real danger combined with poor judgment often leads to accidents.

Caving is not gambling, nor an ‘extreme’ activity where we rely on chance or luck. The risks must be anticipated and reduced or eliminated.


Good and timely organization is important for comfort, efficiency, and safety. 

Case study 

Here we will share our experience of how an objective danger during an expedition provoked a series of risks. Nonetheless, as a result of good organization the safety of the participants wasn’t compromised. 


For almost 10 years now, the club has been organizing the exploration of the Crnopac cave system in South Velebit, Croatia. Exploring the area requires 5-6 days of underground camping and the group of explorers is often more than 10 people. We visit mostly in the fall (October or November). Over the years, we’ve had problems with heavy rainfall and harsh conditions on the 160 m vertical shaft Grlic which turns into a waterfall. You can see more about these expeditions here

The expedition

During our last visit in 2023, we were met by torrential rains. Considering our experience with this region and similar conditions we decided not to penetrate the Crnopac system through the Kita Gacesina entrance. We put into action an alternative plan and transferred to a different region: the Biokovo mountain in Southern Dalmatia, Niemica cave

The heavy rains had passed. Our group consisted of 14 people, and there were various things to be checked in the cave by different teams. Our common goal was to reach the cave bottom at -934 m. You can read more about this expedition here

Our plan was the following:

  • Day 1: reach the cave and descend to the camp at -400 m, base camp
  • Days 2 and 3: exploration and descent of all groups to the bottom at -934 m
  • Day 4 or 5*: exit

*+/- One day depending on what we find and whether there will be more work to be done

On-site organization:

  • the cave is wetter than usual up to -400m, which is normal given the heavy rainfall
  • 1 of the participants decided not to continue after the camp at -400m
  • We divided into 3 groups of 4, 4, and 5 respectively
  • A key moment in the cave is a cascade of 200m immediately after the camp, due to falling rocks
  • two groups will reach the bottom and then return to -400m and one group will sleep at -900m

Unfortunate situation

During Day 2 when all the groups are on site the water level in the cave sharply rises and starts to flow, where it was previously dry. For all the groups in the cave, this has different consequences. The table below presents all the participants, the depth at which they are located, their direction of movement, their task, and how this change in the water level is expressed:

GroupNumber of peopleDepthDirection of movementTask Event
1Four-550mup ⬆Checking a new vertical shaftWaterfalls
2Four-650mup ⬆ClimbingWaterfalls 
3Five-900mdown ⬇To reach the campRising river level
BivouacOne– 400m Welcome groups 1 and 2River in the camp 


All of the risks listed below are present even without rising water levels and the formation of new rivers. but are either extremely low or manageable. Given the water, however, things look different.

  • Large group – The large group is a factor to always be careful with. The chances of something happening to one of the group members or them doing something are big, and the risk is proportional to the group size. During the cave flooding there are 3 groups inside and one participant at the bivouac. Their preparation, reactions, and decisions influence whether an accident is provoked or avoided.   
  • Falling rocks – from -350m to -550m there is a 200m cascade with falling rocks even if you are careful. A fallen rock from the shaft’s top reaches the cascade’s bottom with ricochets. There is a procedure for entering and exiting the vertical in this section, and we are also aware that the timing of the different groups is decisive!
  • Lack of communication – there’s a cable in the cave from the entrance until -400m, meaning after -400m the groups don’t have a connection with each other. The communication and arrangements in the cave are of key importance. A change of plan and timing at the 200m cascade can put one participant or the whole group at risk. 
  • The flood – the sharp rise and approach of the water leads to a bunch of new risks or amplifies the already present ones. The inability to continue in the desired or necessary direction, the guaranteed hypothermia, and the feeling among the participants that we should do something e.g. change the plan are no longer theoretical situations, but real scenes playing out before our eyes.
  • Hypothermia – we need to underline this tangible risk.  
A rescue blanket – the caver’s best friend


Here are the decisions and results of each group at the beginning of the flood: 

  • Group 1 – located very close to the 200 m cascade. They undertake the immediate exit from the new vertical shafts. They are faced with large waterfalls falling down the 200 m cascade. They continue ahead to check the large shaft, and if necessary they can go back. They take into account that if they continue they have to wait for the second group to avoid meeting at the cascade. They keep going and pass the whole 200-meter cascade. Wet and frozen, but well.  
  • Group 2 – they reach the climbing spot at -550m and begin to climb. The water quickly increases its flow rate and the climbing area turns into a waterfall. They go down and wait. They have a primus, food, utensils, a rescue blanket, and a down jacket. They spend 3-4 hours in the improvised bivouac and depart after they decide that the water has drained enough.
  • Group 3 – when reaching the camp they notice that there are newly formed streams with a large flow rate. The main river begins to rise, they monitor the level and rate of rise by placing markers. The camp is the most suitable place in terms of comfort, but if needed they have a place for evacuation. They don’t have to because the water level begins to decrease. They spend the night in the bivouac and the next day, they leave for the camp at -400m. 
  • Camp – a river forms in the bivouac, so it’s moved to meet all the groups. Each group is provided with much-needed hot food, tea, and warmth, regardless of their arrival time.

The following day is used for regrouping and ascending of the 3rd group. Everyone goes out on the 4th day.

Cold shower deep underground

Factors that reduced the risk

What helped in this situation

  1. Plan and communication – due to the specifics of the cave (200-meter cascade), the large group, and the multiple places to explore we not only need a clear plan but also good timing. We need to know which group is doing what and during what timeframe. Everyone knew how to approach, what’s the ideal plan and how much we could deviate from it, without risking the security or the effectiveness of each group.  
  2. Autonomy – each explorer carries a cap/buff, rescue blanket, and a down jacket. Each group has a primus, first aid kit, utensils, and food. This allows for long breaks and an improvised bivouac with a high level of comfort, meaning warmth, food, and tea.
  3. Individual preparation – the groups consist of technically well-prepared members in decent physical shape. Each group has a minimum of one participant with great experience and knowledge of the cave, who acts not only as the group leader but also as the decision-maker. The groups work together well, and apart from making the right decisions have a good time 🙂 
  4. No bullshit – it is the right decisions and the absence of bad ones that optimize the presented context. The absence of undue ambition, impatience, incomprehensible self-centeredness, or outright poor judgment is always welcomed. If you can, please keep these features at home, locked away.
Wet but happy


Even a seemingly safe and problem-free study can turn into a real challenge. Many factors influence such a situation, and the more informed we are, the better we can deal with this type of situation or simply avoid it.

The challenge may come from another incident, e.g. an injury. We never plan for, nor expect this type of incident but must always be prepared for it. In such situations, what we have planned, communicated, and brought with us, combined with our skills and experience will dictate how the events unfold.

Each exploration or even a day trip requires good preparation and knowledge of what and when to expect from the surface, and what we should and shouldn’t do… in short, always keep this in mind.


You can read more on risk evaluation in the article ‘+1, -1, and 0. Risk assessment for outdoor enthusiasts

Text: Tsvetan Kosturkov

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