Arctic scuba diving - What you need to know - Plura Valley

Arctic scuba diving: What you Need To Know for Cold Water Scuba Diving

Scuba Diving continues to gain popularity as a sport worldwide. People from a growing list of nations are strapping on tanks. They want to experience the things we have enjoyed for years. Yet, not all diving is equal. Many environmental factors demand divers change and adapt techniques. This ensures diving is the safest it can be for a given scenario. Diver education and training should stay pragmatic about environmental factors. This allows the sport to take place across many regions. One environmental factor that demands considerable adaptations is cold water. This is especially true in Nordic countries, allowing for arctic scuba diving, or high altitude areas like Switzerland. The water temperatures there rarely get above fourteen Celsius(57.2F), spending much of the year between zero and seven Celsius(32-44.6F).

In this article you will read about adaptations that are required for cold water and arctic scuba diving. Successful cold water diving requires three main adaptations. They are communications, skills and equipment.

The cold water challenge

It is true that the majority of scuba diving takes place in warm water. Dive training agencies have wisely tailored their training and practices to cast the widest net. They cater to the largest group of divers. In warmer waters, rarely would divers use gloves for temperature-related exposure protection. Nor dry-suits with thick undergarments. Thus, most diver training assumes high in-water flexibility and tactile sensation. This is not the case for cold water diving.

Cold water diving and especially arctic scuba diving poses prevalent challenges beyond the obvious hypothermia. But, preventing hypothermia reveals these challenges. Water conducts heat 24.16 times faster than air (often rounded for simplicity to 25). Hence the need for significant equipment adaptations in cold water. Cold water divers wear thick under-suits and heating vests, topped off with thick hoods and either thick wet or dry gloves. Adding this bulk decreases mobility and tactile response. The result is that things take more time to achieve. This could be as benign as retrieving an item from a dry suit pocket. Or more cumbersome, like writing a message to a team member on wet notes.

In warmer waters, a diver may choose to wear gloves. Wet hands can get small abrasions by maniputalting bolt snaps or double-enders. In cold water, especially arctic conditions, abrasions aren’t the main consideration. It is to prevent nerve damage to the fingers caused by cold exposure and minimising DCS risk. Cold water divers opt for thick wet-gloves, or dry-gloves with thick woollen under-gloves. Dry being the better choice. Water temperature and length of dive determine the type. There is a remarkable difference between what is tolerable and safe. For example, diving for 30 minutes in 7 degree water compared to a long decompression dive in 2 degree water. Equipment manufacturers understand this and have designed various gloves. In Nordic regions, a standard 5-finger dry-glove is, often, not suitable. The separation of fingers does not provide adequate thermal protection for longer dives. Many divers (like me) opt for Spock-like dry-gloves, having the hand in a “live long a prosper” arrangement. Others will go as far as a full dry-mitten. It is true these gloves provide greater thermal protection. The trade-off is a decreased tactile response. This demands adaptation. The diver must be able to complete the dive with limited use of their fingers.


When cold water diving, communication can be more difficult. Many hand signals require the independent use all five fingers. With Spock’s or mittens there is less a diver can “say” underwater. That will often mean using wet-notes to write longer messages for team communication. Writing swathes of text on a dive is not particularly practical and can create stall points. You have limited time and gas. So it is critical to choose quality over quantity communication. For divers that dive in a regular team, this is easier. The more a team dives together, the less need there is for bulk communication. Team and situational awareness can proactively diminish unnecessary underwater “chit-chat”. Still, there are crucial pieces of information teams must share to dive safely. To convey this information, cold water divers often dive with a primary light. An essential piece of kit in cold waters, not only for technical, overhead or night dives. This allows a diver to throw an OK or PROBLEM/ATTENTION sign to the entire team with ease. When diving during the day in open-water, a primary light must have enough power to be discernible. Of course, there is other information to communicate while under the surface. An important one is gas pressure. Without 5 independent fingers, this is difficult. So the team needs to agree before entering the water how to communicate it. For instance, instead of relaying gas pressures, the first diver to reach turn pressure signals for attention, then to turn the dive. The team acknowledges the turn signal, and they make their way back. Further, if a diver asks “what’s your gas pressure?”, the team check their SPG’s and signal OK. This means they are either not yet at the turn pressure, or have sufficient gas for the remainder of the plan. These strategies are acceptable if diving in a familiar team, and indeed, how I and my teammates dive. However, in a situation like teaching, an instructor needs to know student’s actual gas. In these scenarios, the divers must know how to indicate their gas pressures.

Below are the standard one-handed number signals when a diver has use of all five fingers. The other is a short video showing how cold water divers can indicate numbers when wearing either a Spock or mitten.

One handed number signals




Remember, no matter which glove you are using, the team must know and agree on how to communicate. Have this conversation before diving, so everyone is cognisant of the expectations.

Skill differentiation and equipment considerations

An area of more deliberate adaptation is in the execution of certain skills and use of equipment. If you dive in warm water, no matter the level, you will need to adapt some procedures for cold water.

DSMB – Most divers learn to send up a DSMB, or “shoot a bag”, early in their diving education. This is one of the best skills to introduce task loading. And, the need to maintain self, team and situational awareness. Instead of writing a how-to on shooting a bag, I will go over specific points salient to cold water diving. The simplest method of sending a DSMB is with the open-ended variety. To deploy these markers the diver enhales their exhaust gas(2nd stage bubbles) into the opening and up it goes. It is a reasonably safe option for recreational diving. And, one of the fastest ways of getting the bag sent. However, this method is not ideal on technical or cold water dives. In both scenarios, divers carry more equipment creating bulk. The additional gear creates space for entanglement when the spool and DSMB are held so close to the divers second stages, hoses and wrist mounted equipment. Therefore, an open-ended DSMB is unsuitable for use in cold water.

The better type of DSMB is fully closed, with a one-way inflation valve and an over-pressure valve. To inflate this type of marker use the LPI hose from the wing/dry-suit, or place the lips around the nipple on the one-way valve and exhale into it. Both of these methods are acceptable when cold water diving. However, both require a higher degree of awareness as there is a risk of entanglement. That risk is entirely manageable by the diver with regular and thoughtful practice. And, the other team members should keep watch for potential entanglements. In cold water it can be difficult to seal the lips around the one-way inflation valve due to numbness. It takes practice. There is no substitute for skill repetition in this environment.

An example of a closed DSMB

SpoolsFinger spools are a great tool and have a slew of uses. Regardless of the spool’s specific use, it needs to work, and the diver needs to be able to work it. When a diver has independent fingers, they deploy a spool by holding the central hole between the thumb and forefinger. Or, they do so with the forefinger inserted through the hole. If, like me, you dive a Spock dry-glove, or a dry-mitten, one alternative is to use the thumb. The central hole for most spools is able to accommodate the thumb with a thick wet/dry glove. But, this isn’t always feasible. The thumb is shorter than the forefinger so the spool can spin off and pay out line, creating a spaghetti mess. A more controlled way of handling a spool is to use it the same as you would with independant fingers. With Spock dry-gloves, you can manage to grasp the spool between the thumb and first two fingers. It will then spin and pay out line as needed. This also works with dry-mittens. Use the thumb and the edge of the mitten surface along the forefinger towards the tip. Using a spool with these types of gloves requires practice and awareness—it will not feel the same as it does with bare hands. Another option is the so-called cold water spool. These spools a double-ender as a winding device while the thumb is through the central hole. It can help with taking the line in, but it doesn’t have any practical advantage when paying out line.
When using the spool to send a DSMB, there is a simpler method available. Instead of holding the spool, clip the double-ender to the line and hold it instead. The spool is able to free spin in place as the DSMB ascends to the surface. Once the line reaches the surface, you can catch and wind the spool tight. Then you can clip off the double-ender, as in any DSMB deployment.

Storage is another topic of adaptation when cold water diving. Spools often get stored with the loop end of line pushed through one of the smaller edge holes and secured to a double-ender. The excess line is then wrapped wo or three times around the shaft of the double-ender and secured through the gate. This method means the risk of it accidentally coming undone is effectively zero. However, a diver wearing Spock’s or dry-mittens can’t feel well enough to deploy a spool setup like that. Even five-finger dry-glove users wearing thick under-gloves often lack the dexterity. This is further exacerbated in a situation where a diver may have lost all visibility, e.g. a silt out in a cave. In any situation, a prescient diver makes sure their equipment is easy to access and use. Cold water diving impels the diver to stow their spool(s) in such a way that time is not wasted trying to deploy them. The simplest method is usually the best. So place the line’s loop through the gate of the double-ender and then clip it to a small hole on the spools edge. This means the spool can come undone easy. Therefore, it lives clipped in a dry-suit pocket or sidemount pouch, as opposed to the butt D-ring.

Blind gas sharing

Plura Valley is a technical cave diving centre in Northern Norway. To avoid truncating the article, it’s worth mentioning something specific to caves. One method for blind gas sharing requires high tactile feedback. The diver signals “out of gas” with the hand already on their teammate for touch communication. Then, keeping that hand in place, they place their other hand open by the chest of the donor. They wait to receive the 2nd stage from them. Not the preferred method in this situation, but an acceptable one. In cold water, the lack of fine feeling doesn’t make this option practical, or safe.
If you are doing cold water sidemount diving in an overhead environment, it is impractical to donate a cylinder. Cold water divers almost always choose steel cylinders for their back-gas. They use them as part of their ballast system. As such, donating a cylinder is unwise at best and dangerous at worst.

The safest method no matter the open circuit configuration, is as follows. The out-of-gas diver signals that they are “out of gas” as previously mentioned. Keeping one hand on their teammate, the other hand follows then line to the donors hand. Then the receiver traces the donor divers body from their hand, up their arm to the 2nd stage in their mouth. The receiver then gently twists the 2nd stage twice. This lets the donor know they wish to take the regulator. The donor releases their teeth from the mouthpiece. The receiver can get gas as the donor retrieves their short hose regulator at the same time. Be aware that we use the twisting method for practice. In a real out-of-gas situation, the donor knows they need to release the long hose. They know this due to the out-of-gas signal from the reciever. The receiver can then trace the body and grab the second stage. This skips the need for twisting.

It’s worth noting, if the donor is diving sidemount and the short hose is already in the mouth. The donor can break-away the long hose. They can then hold it in front of the regulator in their mouth for the receiver to grab. Alternatively, the receiver can feel for a 2nd stage clipped off at the shoulder D-ring. If it’s there, they can break-away the regulator and start breathing from it. Regardless of the style of glove a diver is using, this method works.

Cold water diving places exigencies on a diver’s equipment, procedures and communication. It forces divers to be more deliberate in the ways they operate in the water. Also to create pragmatic adaptations. Divers and dive teams need to be prudent with any changes they make. Changes should only occur if they improve practicality and safety. With all manner of diving, there is no substitute for practice. We need to drill each change, and be critical in our interrogation of them. This will make dives as safe and efficient as possible. The more extreme the environment, or more demanding the dive, the more meticulous divers must be.

Arctic scuba diving courses​​

Cold water scuba diving and arctic scuba diving are two types of underwater exploration that involve diving in low-temperature waters, but they differ mainly in the extremity of conditions and the equipment required.

Getting ready for some ice diving. Model: James Allen

At Plura Valley the water is cold year round and this offer the unique possibility to consistently practice cold water scuba diving. In the winter seasons things are turned up a notch, this is when the real arctic diving conditions occur. During this period the ice diver courses take place and where much of the water reaches a near freezing point. You will also never find more pristine waters than during this period with visibility up to a 100 meters (330ft.).

Interested in ice diving or other scuba diving courses? Press the links below and read all you need to know about our selection of courses and trainings!

Ice diving course

Diving Course calendar



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