The 120 Degree Rule ©

 

 

Picture by the Author.

Let’s face it, falling into cold water can kill you, everyone knows that, right!

 

Well, maybe everyone doesn’t know that because every year someone doesn’t pay attention to the “120 Degree Rule” and the “5 Golden Rules” of cold-water safety, and they go out on the water before it is warm enough, without the proper gear, fall in and die.

 

Cold water is no joke, in fact over 50% of the people who find themselves suddenly immersed in cold water will die!

 

An excerpt from A Pocket Guide to Cold Water Survival, by the Coast Guard, page 1, HERE.

The “120 Degree Rule”¹ is a rule of thumb that paddlers use to decide if it is safe to be on the water without any protective immersion wear, like a dry-suit or a wetsuit.  If the air and water temperatures add up to less than 120 degrees then, according to the rule, it is not safe to go out on the water without a dry- or wetsuit on to protect you if you should fall in.  The 120 Degree Rule is a good rule of thumb, but like all rules of thumb there is an exception, and it is cold water and “Cold Shock”!

 

An excerpt from A Pocket Guide to Cold Water Survival, by the Coast Guard, page 12.

“There are a few, uh, provisos.  Ah, a couple of quid pro quo...”

Genie in the Disney movie Aladdin (1992)

 

The problem with the 120 Degree Rule is that it can give you a false positive and tell you that it is safe to be out on the water without protective gear when in actuality, isn’t safe at all. 

 

As an example, what if it is an unseasonably warm day in the early spring, just after the ice is off the lakes and creeks.  The air might be 70^o F (21^o C), or even as much as 80^o F (27^o C) and when you add this unseasonably warm air to that of the water temperature, the 120 Degree Rule would show that it is safe to be on the water without protective clothing, even when the temperature of the water is only between 40^o to 50^o F (4^o to 10^o C) – this is cold water and these are not safe water temperatures!

 

In reality, air temperature has nothing to do with how safe cold water is, because when you are in cold water the only thing that matters is the temperature of the water.²

 

Cold water is defined differently depending on who you ask, but the temperature is higher than you might think.  This is because of one very important fact, which is that you lose body heat 25 times faster to water than you do to air, so a nice day with an air temperature of 70^o F (21^o C) feels far different from the cold water of a 70^o F (21^o C) lake.  Cold water is described by Alaskan sources as NY water under 77^o F (25^o C), in British Columbia cold water is water below 70^o F (21^o C) and the American Canoeing Association (ACA) recommends wearing protective clothing if the water is less than 65^o F (18^o F).³

 

From the National Center for Cold Water Safety, HERE.

Water temperature below 77^o F (25^o C) can affect your breathing if you fall in it and if you are immersed in water between 60^o F and 50^o F (15^o C to 10^o C) you can experience “Cold Shock”⁴.  Cold shock is a series of physiological responses that happen to you when you are suddenly dumped into water that is below 60^o F ( 15^o C).  Stage one of cold shock is you will lose control of your breathing and you will take a several, sudden deep gasps, or gulps of air.  If your mouth is below the water when this happens, you will breathe in water, drown and die.  This is one of the reasons why it is important to wear a life preserver, as it lessens the chance that your mouth is underwater when you begin to gasp.

 

In stage two of cold shock, if you have not sucked in a double lung full of water and are not now drowning, you will begin to hyperventilate and lower the carbon dioxide in your blood.  This will make you feel dizzy, faint, weak, you might feel cramping in your muscles or numbness in your fingers and toes, you might even experience a ringing in your ears or unconsciousness.  If you lose consciousness and are not wearing a life preserver you will drown and die.

 

If you stay conscious, you will find that you can’t coordinate your breathing with your swimming, which will make it difficult to swim or keep your head above the water.  Again, if you are not wearing a life preserver, at this stage of cold shock you will drown and die.

 

“But I always wear a life preserver”, you say, “so I don’t have to worry about cold shock, right”?

 

Well that depends on your age and level of cardio-respiratory fitness because the cold water will cause the blood vessels in your arms and legs to constrict, increasing the blood pressure in your torso, neck, and head.  If you already have high blood pressure or clogged arteries, especially in those around your heart, you could have a sudden heart attack or a stroke and die even if you are wearing a life preserver!

 

Keeping the heat in, an excerpt from A Pocket Guide to Cold Water Survival, by the Coast Guard, page 2.

“Well, what should I do to avoid cold shock and death”, you ask?

 

First, you should avoid going out onto the water until it is warmer than 77^o F (25^o C), but if you are going to go out onto water that is colder than 77^o F (25^o C), then you should follow the “5 Golden Rules” of cold-water safety, which are

1. Always wear your life preserver (PFD)

2.   Always dress for the water temperature

3. Field test your gear

4. Swim test your gear every time you go out

5. Remember it can happen to you, so plan for the worst

 

An excerpt from A Pocket Guide to Cold Water Survival, by the Coast Guard, page 11.

First and foremost, because this rule is often disregarded, always, always, ALWAYS wear a life preserver (PFD) whenever you are on the water, it will save your life in the event of an accident!

 

Second, use the 120 Degree Rule AND the water temperature to help you decide on how to dress.  If the combined air and water temperature are below 120^o and/or the water temperature is below 60^o F (15^o C), or even 77^o F (25^o C) if you want to be conservative, wear a wetsuit, or a dry-suit with a base layer and an insulating layer underneath it (for more on layering read “The Top Ten Wilderness Survival Skills...Number One ©”, HERE.).  Remember, wool is always a good insulating layer when on the water, because it keeps you warm even when it is wet.  Check or field test your protective layers to make sure that they will keep you warm and for how long they will keep you warm.  Swim test your protective gear, every time you go out, to make sure that there aren’t any leaks, weak gaskets and that you are properly zipped up.

 

So, next time you think about going out on those spring waterways, check the water temperature and take the proper precautions so you don’t end up as a Coast Guard statistic!

 

Don’t forget to come back next week and read “Wild Garlic, One of the First Plants of Spring©”, where we will talk about this early spring plant.

 

I hope that you continue to enjoy The Woodsman’s Journal Online and look for me on YouTube at BandanaMan Productions for other related videos, HERE.  Don’t forget to follow me on both The Woodsman’s Journal Online, HERE, and subscribe to BandanaMan Productions on YouTube.  If you have questions, as always, feel free to leave a comment on either site.  I announce new articles on Facebook at Eric Reynolds, on Instagram at bandanamanaproductions, and on VK at Eric Reynolds, so watch for me.

 

That is all for now, and as always, until next time, Happy Trails!

 

 

Notes

 

¹ In areas where Fahrenheit is not used and Celsius is, this rule should be called the “50 Degree Rule”, since 50^o C is just a little bit more than 120^o F (120^o F is 48.9^o C).

 

² For more on cold water safety, I highly recommend the National Center for Cold Water Safety, HERE.

 

³ From Radford Bean’s article “Cold Water Immersion—It’s a Life or Death Matter”, which is an excellent article, that I highly recommend (it can be found HERE).  The author also states that according to the Coast Guard statistics, 75% of all canoeing and kayaking fatalities occur in water with a temperature below 65^o F (18^o C).

 

⁴ Earlier this year, in Russia, as part of annual Orthodox Epiphany celebrating Jesus’s baptism, a 38 year old man and a 40 year old woman drowned after jumping through holes chopped into a frozen river (one died on the Chortomlyk river and the other drowned in the Oredezh river).  River currents were blamed for sweeping the two away under the ice, but while it is not stated, cold shock would also be a likely culprit.

 

For more information see “Freezing for their faith”, HERE, “Husband drowns in front his wife...”, HERE, and “Distressing moment Russian lawyer, 40, is swept away...”, HERE.

 

 

Sources

 

Angler Aid; “Cold Water, Use The 100 Degree Rule”, [© Copyright 2019], https://angleraid.com/2019/04/23/120-degree-rule-cold-water-immersion/, accessed May 1, 2016

 

Bean, Radford; “Cold Water Immersion—It’s a Life or Death Matter”, February 20, 2018, [© 2013 by Canoe & Kayak Oregon], https://www.canoeandkayakoregon.org/single-post/2018/02/20/cold-water-immersion-it-s-a-life-or-death-matter, accessed May 1, 2022

 

Bending Branches; “Winter Paddling Safety”, February 8, 2021, [© 2022 Bending Branches], https://bendingbranches.com/blogs/resources/winter-paddling-safety, accessed May 1, 2022

 

BoatUS; “The Cold Facts on the ‘120-Degree Rule’ ”, November 14, 2016, [© 2022 Waterway Guide Media LLC], https://www.waterwayguide.com/latest-news/news/7385/the-cold-facts-on-the-120-degree-rule, accessed May 1, 2022

 

Coast Guard, Department of Transportation, A Pocket Guide to Cold Water Survival, CG 473, September 1975, https://books.googleusercontent.com/books/content?req=AKW5QafxNJBmiIml6O4jiudRpr2rz8pLfodQOiq-4gZNh4xa5uIN_rq05C2yAes1AYw67Ziq189QaQaFDHBHE0SJivfCxjMW1DReANLjFqw1qX6jEl2mz1HPKXj4BRQJv8zAOcO6oDE70Dcv__VE2uPh4tEqLSzMxDRiWOv3p6ssyQjE2bevJMX7-Ol2KDtIPQVcVuaJudJMLaOOuSUVs8qYS1Nlaxnm47GVOCXLR79KzL6nV3R0zZG4DxRt9hoYrIRGugXm6RVfbU2gxeix7JLKbxpvQsNB9w, accessed May 1, 2022

 

Cold Water Safety; “Five Golden Rules”, [National Center for Cold Water Safety], https://www.coldwatersafety.org/golden-rules, accessed May 1, 2022

 

Cold Water Safety; “Rule 2, Always Dress for The Water Temperature”, [National Center for Cold Water Safety], https://www.coldwatersafety.org/dress-for-the-water-temperature, accessed May 1, 2022