National Weather Service United States Department of Commerce


Cold Water Can Be Dangerous

Warm air doesn’t always mean warm water in lakes, streams or oceans. Fifty five degree water may not sound very cold, but it can be deadly. Plunging into cold water of any temperature becomes dangerous if you aren’t prepared for what the sudden exposure can do to your body and brain. Warm air temperatures can create a false sense of security for boaters and beach goers, so if you are planning to be on or near the water, arrive knowing the conditions and how to protect yourself. Cold water quickly removes heat from the body which could lead to cold water shock within the first minute, loss of muscle control within 10 minutes or hypothermia within 20 to 30 minutes. When your body hits cold water, “cold shock” can cause dramatic changes in breathing, heart rate and blood pressure. The sudden gasp and rapid breathing alone creates a greater risk of drowning even for confident swimmers in calm waters. In rougher open water this danger increases. Unplanned immersion in cold water can be life-threatening for anyone without protection from the temperatures or a lifejacket to help you stay afloat. When Cold Shock and Hypothermia begin to impact your ability to think and act, lifejackets and floatation can create extra time for help to arrive or for you to get out of danger. Even the most experienced cold water surfers, swimmers or boaters know to prepare for the conditions.


+Understanding the Danger of Cold Water

Knowing what happens when you enter cold water and what you can do in those first seconds could save your life and give time for help to arrive.


  • Gasping for Breath & Rapid Breathing (2-3 Minutes or More)
    Cold Water Immersion can trigger involuntary gasping, rapid breathing or hyperventilating due to the “shock” of sudden immersion. This uncontrolled rapid breathing can quickly create a drowning emergency if you inhale water and cannot stay afloat.
  • Heart and Blood Pressure Problems
    Cold water can cause a sudden spike in heart rate and blood pressure. This increase can cause heart failure and stroke for vulnerable people.
  • Cognitive Impairment
    Cold shock can cause an immediate panic, fear or stress reaction that then impairs clear thinking and decision making. Extended exposure and the onset of hypothermia can further hamper cognitive ability and the ability to choose the right actions to avoid severe injury or death.

Physical incapacitation is a loss of muscular control in the arms, legs, hands and feet, and the impact can be felt within seconds of entering cold water. The longer the exposure, or the colder the water, the more severe the impact can become. With a loss of muscular control to keep your head above the water, along with the lack of a lifejacket or floatation device, drowning will become inevitable. Symptoms may include weakness, exhaustion, and an inability to control fingers, hands, arms or legs. The progressive loss of muscular control makes staying afloat without assistance or self-rescue virtually impossible.

The onset of hypothermia begins with a core body temperature to 95F (35C). Beyond the initial dangers of cold shock in the first 1 – 3 minutes of immersion a person’s body temperature will continue to drop increasing the risk of drowning or death. As the core body temperature continues to drop the impairments to physical and cognitive ability also increase until drowning or death without rescue become inevitable.

If you get yourself or help someone else escape from cold water, get into a warm, dry, protected environment as quickly as possible. Even removed from cold water a victim’s core temperature can continue to drop to dangerous levels.


Cold water risks include immersion into any body of cold water: oceans, lakes, rivers, streams or pools. In many places, parts of the year and bodies of water warm air temperatures may not coincide with safer, warm waters. Many areas of the country have warm days and yet the water stays cold. In the Pacific Northwest ocean temperatures may stay in the 60’s. Weather conditions along any large body of water can cause dramatic drops in water temperatures even in the middle of summer. In the waters around Annapolis, MD temperatures may only be above 60F for 5.5 months of the year. Cold Shock and the dangers of sudden cold water immersion can happen along almost any shore at any time of the year. Water activities that put people at risk include kayaking, canoeing, whitewater rafting, paddle boarding, and lake boating.

Risks that may cause immersion in cold water include:

  • Turbulent water, waves and surf which can overturn watercraft or fill a boat with water.
  • Falling off watercraft, docks, rocks or jetties.
  • Falling through the ice.
  • Sneaker waves that can pull beach walkers into the surf.
  • Rising tides, rising rivers, tidal currents and rip currents.
Even when the air is hot, water can be cold! Always wear a life vest. Even experienced swimmers can quickly lose muscle control. Cold water can kill.


Being prepared for an outing on cold water means being prepared for the possibility of suddenly being immersed into cold water. Your ability to survive cold water immersion depends on your ability to stay afloat and to stay warm until help arrives. Below are several things to consider prior to venturing out on cold water.

  • Always wear a life jacket in and around the water.
  • Always dress for water temperature, not for air temperature.
  • Some examples are:
    • Wet suit
    • Dry suit
    • Immersion suit
    • Survival suit
    • Exposure coveralls
  • Carry an Emergency Position Indicating Radio Beacon (EPIRB), personal locator beacon (PLB) or VHF Radio.
  • File a float plan with someone you trust. The plan should include details about the trip, boat, passengers, towing or trailer vehicle, communication equipment, and emergency contacts.
  • Know Before You Go:
    • Be sure to check the weather and water temperature before you go out on the water
    • If water is too cold, consider staying off/out of water until water is warmer

+Take Action

Cold water can kill. The following guidelines and images from the U.S. Coast Guard will increase your chance for survival:

  1. Stay calm.
  2. Minimize time in the water. Get out as soon as possible safely.
    • If possible, utilize any floating objects to get out of the water.
    • Keep as much of your body out of the water as possible.
  3. Evaluate your options.
    • If you can swim to safety, stay calm and do so.
    • If you cannot swim to safety, conserve energy and heat and await rescue.
  4. If you cannot get to safety, assume the Heat Escape Lessening Position (H.E.L.P.) position. This protects the critical body areas and slows down the loss of heat. H.E.L.P position means:
    • Draw your knees to your chin and keep your legs together.
    • Press both arms against your side and keep your head out of the water.
  5. If possible, form a huddle in the water with others to conserve body heat.


Huddle position

If you need to treat yourself or someone else that has been submerged in cold water, follow the steps below (developed by the Red Cross):

  1. CALL 911 or the local emergency number.
  2. Gently move the person to a warm place.
  3. Monitor breathing and circulation. Give rescue breathing and CPR, if needed.
  4. Remove any wet clothing and dry the person.
  5. Warm the person slowly by wrapping in blankets or by putting on dry clothing.
  6. Hot water bottles and chemical hot packs may be used. Wrap the person in a towel or blanket before applying.
  7. Do not warm the person too quickly. Do not immerse the person in warm water. Rapid warming may cause dangerous heart arrhythmias.
  8. Warm the core first (trunk and abdomen), not the extremities (hands, feet). Warming hands and feet first and can cause shock.

+Resources, Links and Partner Information