Well, the groundhog recently said we’ve got a few more weeks of winter, so today let’s talk about what you should know about falls through the ice.
In the winter, northern regions with lots of water features become vast fields of ice. Since the shortest distance between two points is a straight line, you may be tempted to cross that frozen lake rather than go around it. That’s fine if the ice is thick, but there’s a risk of falling through the ice. If so, you’ll be in extremely cold water (and extremely big trouble).
How thick must the ice be to sustain the average person’s weight? At least 4 inches for any reasonable activity like walking or cross-country skiing. On a snowmobile or all-terrain vehicle, at least 5-6 inches would be required. Always stay off ice that’s thought to be 3 inches thick or less, especially in warmer days where ice may be thawing. Note that sea ice is weaker and requires a greater thickness to support the same weight as fresh water ice.
HOW YOUR BODY LOSES HEAT
Your body has various methods it uses to keep its internal core temperature at appropriate levels. The “body core“ is composed of the major internal organ systems that are necessary to maintain life, such as your brain, heart, liver, and others. A drop in the core temperature of just four degrees below normal may cause ill effects due to the cold, a condition known as “hypothermia.”
In cold weather, your blood vessels constrict involuntarily to conserve heat. Muscles “shiver” as a method of heat production. As well, you can voluntarily increase heat with exertion; that’s why it’s recommended to “keep moving” in cold environments.
When the body is exposed to severe cold, as in the case of a fall through the ice, it’s difficult to maintain a normal core temperature. Cold water, being denser than air, removes heat from the body via a process called “conduction.” Water “conducts” heat away from the body much faster (some say 32 times faster!) than air does. The higher the percentage of body surface submerged, the faster it loses heat.
THE 1-10-1 PRINCIPLE
The U.S. Coast Guard 1-10-1 Principle gives us a sobering glimpse on your prospects if you have to spend time in icy cold water. What’s 1-10-1
1 minute, You need to gain control of your breathing in the first minute to avoid drowning
10 minutes – You have ten minutes to realistically help in your own rescue. Cold temperatures will cause loss of sensation and motor control of muscles, leading to what is known as “swim failure.” After ten minutes, victims in cold water without a life jacket will drown.
1 hour – You have one hour (maybe more, maybe less) before hypothermia renders your unconscious. One major factor is, of course, the water temperature. Another variable is the amount of body fat the victim has. Body fat helps conserve heat and may increase the time interval before the patient becomes hypothermic.
Take the example of passengers on the Titanic. Unless there was a seat on a lifeboat available, they ended up in 40-degree water. Within ten minutes, they were likely unable to help themselves in any significant way.
The Gasp Reflex
When a person falls through the ice, they experience a physiological reaction known as “Gasp Reflex”, sometimes called the “Inhalation Response.” Where the body is suddenly immersed in temperatures, say, below 70 degrees Fahrenheit, the Torso Reflex causes the victim to involuntarily gasp.
This reaction is meant to increase oxygen intake into the lungs and increase metabolism to build internal warmth. When the head is below the surface, however, the sudden urge to breathe causes water to be inhaled instead of air. When this happens, airways can go into spasm, causing the disoriented victim to panic. Coupled with a massive release of adrenaline, as well as sudden changes in heart rate and blood pressure, many lose the ability to perform the actions that might save their lives.
Although some aspect of the Torso Reflex occurs in just about everyone who is immersed in cold water, the response seems to be variable among individuals. Immersions involving the face seem to be the most severe. Some outdoorsmen who regularly kayak in northern waters, however, appear to be affected less often. This may be due to acclimation to the cold or experience with multiple “dunkings” over time.
What To Do If You Fall Through The Ice
Spread arms wide and kick to get horizontal
Certainly, a fall through lake ice can be life-threatening, but your chances of surviving are much greater if you know what to do. If you can keep it together mentally, a few simple steps might save your life.
Stay Calm: The shock of a sudden immersion in cold water makes it difficult to think as well as breathe. In some circumstances, you may realize the ice is going to break under your weight. Faced with this, it’s important to brace yourself and try not to inhale water if you go under. This will be difficult, but more possible if you have some warning that a dunking is imminent.
The gasp reflex we talked about last time may be prevented by covering your mouth and nose with your hands before getting immersed. If you can establish the “seal” as you enter the water, you’ll have a better chance of not drowning. This procedure should be taught to everyone spending time in proximity to cold water and should be maintained until the head is above the surface.
Make every effort to keep calm. You have a few minutes to get out before you succumb to the effects of the cold. Panic is your enemy.
Get Your Head Out Of The Water: This is best accomplished by breathing in and bending backward as soon as you get your head out of the water. If there are others nearby, shout that you’re in need of emergency aid.
Get Rid Of Heavy Objects That Weigh You Down: The more you weigh, the harder it will be to get your body out of the water.
Tread Water And Turn: Treading water by kicking with your legs will help get you horizontal and raise you further out. Quickly turn your body in the direction where you came from; you know the ice was strong enough to hold you there.
Try To Lift Up Out Of The Ice: Place your arms on the ice spread widely apart in front of you. Kick with your feet to give you some forward momentum and try to get more of your body horizontal and out of the water. Lift a leg onto the ice and then lift and roll out onto the firmer surface.
Do Not Stand Up: Keep rolling in the direction that you were walking before you feel through. This will spread your weight out, instead of concentrating it on your feet. Then crawl away until you’re sure you’re safe.
Get Warm As Soon As Possible: You’re out of the water, but you’re not out of the woods! Get to a warm place if possible. Hypothermia is highly likely and soaking wet clothing isn’t helping. Having spare clothes or a blanket available in a hiking partner’s backpack is an important consideration. So is having a way (or two or three) to start a fire if no heat source is at hand.
Changing into dry clothing should be accomplished immediately and before starting a fire; external heat sources aren’t very effective in penetrating wet clothing. It’s possible that you may have to change outdoors. If so, stay out of the wind by standing behind a large tree or some other barrier.
Once you have access to a heat source, get close enough to feel the warmth and bring your knees to your chest with your legs tightly together. This will help conserve body heat. Have others share body heat with you if possible.
PREVENTION
Of course, an ounce of prevention is worth a pound of cure. Avoid situations where visibility might be reduced, such as traversing frozen lakes at night or during heavy snows. Even in conditions that afford good vision, stay clear of unfamiliar terrain.
Any backcountry travel plans should be shared with others that can send for help if you don’t reach your destination or if your return is overdue. This is good policy in any season.
Once you are on the ice, see if there are any cracks or abnormal surfaces. The strength of the ice is not the same everywhere on the same body of water. Beware of flowing water at the edges, springs underneath, and ice that has thawed and refrozen.
Although by no means can ice safety be guaranteed on sight alone, the colors of the ice may give you a clue:
- Blue-Clear Ice: Thought to be the highest density, but only safe if 4 inches thick or greater.
- White-Opaque Ice: Snow freezes and forms a second layer above the main body of ice. Often weak due to air pockets between layers. Snow can also act as an insulator and warm up the ice,thus weakening it.
- Mottled Ice: This ice is unsafe due to thawing and deteriorating at the center and base.
- Gray or Black Ice: Low density melting ice; unsafe.
mottled ice
FLOTATION
You might consider a life jacket to be overkill on a winter hike, but it can prevent a tragedy if you fall through the ice. The Coast Guard has an approved flotation jacket that is brightly-colored and water-resistant. Some additional items useful to get out of the water include ice picks and a length of rope. Having a whistle as a noisemaker may alert others that you’re in trouble.
An air bag accessory is now available for those who are traveling in snow country. Although meant to help survive an avalanche, it can be easily deployed to achieve buoyancy in the water as well.
What kind of flotation device is best? The one you’d actually be willing to wear.
Joe Alton MD
Dr. Alton
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