October 4, 2012
Cold Water Immersion: Know The Risks
There’s no better way to spend the fall than getting out for a boat ride. However, the beautiful fall colours and fresh crisp air can be a distraction from the serious risk of Cold Water Immersion.
If you’re heading out for a fall boating or fishing trip keep the following in mind:
According to the Lifesaving Society of Canada the majority of cold water fatalities occur close to shore and victims are typically thrown unexpectedly from their boats without wearing a Lifejacket or PFD:
- Out of 130 boating deaths, 60% drowned in water under 10 degrees C
- More than 82% were not wearing (or incorrectly wearing) a Lifejacket or PFD
- 63% were less than 15m from shore/safety
- 26% were thrown overboard
- 48% were in a boat that capsized or was swamped
The implications are simple. You can maintain your safety so long as you are knowledgeable of the risks, know how to perform the survival techniques and are wearing a properly fitted and approved Lifejacket and appropriate cold water/weather boating gear.
Expect The Unexpected
Knowing what to do if you’re unexpectedly immersed into cold water dramatically increases your chance of survival. Immersion in cold water can result in cold shock response, incapacitation, hypothermia and cardiac arrest.
“1-10-1” is an easy way to remember the first three phases of cold-water immersion and the approximate time each phase takes.
The phases of Cold Water Immersion are:
- Cold Shock Response
- Cold Incapacitation
Phase 1: Cold Shock Response – 1 Minute
Cold Sock Response refers to the affect of cold water immersion on your breathing, and can last for about a minute after immersion in cold water. The Shock Response starts with an automatic gasp reflex that is the result of rapid skin cooling and can be occur when a person experiences sudden or unexpected immersion into water 15 C or below. If the head is below water, the victim can involuntarily ingest water. If not wearing a lifejacket or PFD drowning can easily result.
In addition to the initial gasp reflex, Cold Shock Response can include hyperventilation. This is the body’s natural reaction to cold immersion. Panic can prolong the body’s physiological reaction; prolonged hyperventilation can lead to fainting. Again, if the person is not wearing a PFD or Lifejacket, their life can be in danger.
Muscle spasms and a rise in heart rate can also occur during the Cold Shock Response phase. In addition, the arteries narrow, and the heart has to work much harder to pump blood throughout the body. This response can trigger cardiac arrest (heart attack), especially in those who have a pre-existing heart condition.
- Cold water can paralyze your muscles making it very difficult to put on a Lifejacket or PFD in the water, so it is very important that you and your passengers are wearing one at all times when on board.
- If you’re heading out in early spring or fall be sure to equip yourself and your passengers with appropriate cold water/weather boating gear (see below).
- If you experience Cold Shock Response you should concentrate on avoiding panic and getting control of your breathing. Wearing a Lifejacket or PFD during this phase is critically important to keep you afloat and breathing.
Phase 2: Cold Incapacitation – 10 Minutes
Cold Incapacitation occurs approximately within the next 10 minutes of cold water immersion. Victims will lose the effective use of fingers, arms and legs for any meaningful movement. Swim failure will occur within these critical minutes and if you are in the water without a Lifejacket or PFD, drowning will more than likely occur.
You should concentrate on self-rescue initially. If self rescue is not a viable option, prepare to have a way to keep your airway clear and wait for rescue.
Phase 3: Hypothermia – 1 Hour
Even in ice water it could take approximately 1 hour before becoming unconscious due to hypothermia. You should learn techniques of how to delay hypothermia, self-rescue, and calling for help in order to increase your chances of survival. In hypothermia, your core body temperature drops below normal levels resulting in weakened muscular functions, reduced coordination and slowing mental functions.
Techniques for Delaying Hypothermia
If you find yourself alone and exposed to cold water, use the Heat Escape Lessening Position (H.E.L.P.) to reduce heat loss from your core body temperature and delay side effects of hypothermia.
H.E.L.P. is performed as follows:
- Cross your arms tightly against your chest.
- Draw your knees up and against your chest.
- Keep your head and face out of the water.
- Take BOATsmart! Canada’s Online Safe Boating Course to learn more about the stages of hypothermia and rescue procedures.
If you and your passengers find yourselves exposed to cold water and are unable to swim to shore or climb onto a floating object, you should assume the “Huddle Position” to delay the onset of hypothermia and increase your survival time:
- Place your arms around each other’s mid to lower back and pull together so your chests are close to each other’s sides
- Intertwine your legs
- Place any children in the middle of the huddle
- Keep unnecessary movements to a minimum in order to conserve energy
Cold Water / Cold Weather Survival Gear
- Always Wear a Personal Floatation Device (PFD) or Lifejacket when boating. More information on Personal Flotation Devices and Lifejackets.
- Have extra layers of dry, light clothing and a water or wind proof outer layer on board.
Gear specific to cold environments offers better protection against the elements and can delay the effects of hypothermia:
- Wet Suit: traps and heats water against the body and should be used with a floatation device. Fluid and Speedo brand wet suits are available at Canadian Tire. Many people wear wet suits when doing water sports such as wakeboarding or waterskiing to prolong the length of their season.
- Dry Suit: Remains dry on the inside and should be used with a floatation device and thermal liner.
- Survival Suit: Helps retain body heat and works as a full body floatation device.
- Immersion Suit: To be used in extreme conditions when abandoning a vessel.
- Exposure Coverall: A PFD with thermal protection
Be sure to choose the cold weather protection gear that is appropriate for your boating activities.