Hypothermia Claims another Hiker

[AdeInTokyo]

Toddy, I should clarify that the temperature range you cite is when hypothermia is surprisingly common. In the case of the hiker, news reports state the overnight temperature she faced was at or below zero (-17 C).

- Woodsorrel

I think I remember a ray means survival show about a couple of Kiwis that got caught out in the mountains. Think I remember that saying that it is more common above freezing, and people rarely go out in near Arctic conditions without proper gear.

But an autumn hike can start off warm, you get sweaty. Then get lost, and try to spend the night shivering and cold.

Not so long ago i was at my hunting permission and decided to camp overnight.i had a hammock no underquilt and a 1 to 2 season sleeping bag. I didnt have much in the way of spare clothing.i wore everything i had and managed a chilly few hours sleep.all th8s was on a unusual cold night in October.
I was up at about 5 am shivering and a sense that all was not well.i made a brew and subsequently knocked it over spilling the lot.i needed a hot drink so made another.i picked myself up and walked to my car 50 yards away to a heater and sleep.why i didnt make that decision earlier still evades me to this day.

 

[Toddy]

Toddy, I should clarify that the temperature range you cite is when hypothermia is surprisingly common. In the case of the hiker, news reports state the overnight temperature she faced was at or below zero (-17 C).

- Woodsorrel

Now that makes sense. At normal everyday temperatures a normally fit person would just shiver themselves warm (and dry) if they can find shelter. Might not be fun, and very uncomfortable, but it's rarely a death sentence to get soaked. It happens all the time. We live in a wet bit of the world. If we didn't get wet, we'd get nothing done, iimmc.

M

 

[SGL70]

Hypothermia is a mean one.
I wrote a bit (signs/effects/how to prevent)about it here

 

[EddieP]

Just above freezing is worst as humid air takes more heat with it and water is wet, so can soak you.

Below freezing the air is dryer and snow brushes off without soaking your insulation.

 

[Drain Bamaged]

In truth it's CIRCUMSTANCES rather than the thermometer that dictate it...........do not become fixated solely on temperature.

D.B.

 

[EddieP]

In truth it's CIRCUMSTANCES rather than the thermometer that dictate it...........do not become fixated solely on temperature.

D.B.

I totally agree, but the risks are counterintuitive to some degree, education is the key to effective risk assesments.

 

[Fraxinus]

Hypothermia is a mean one.
I wrote a bit (signs/effects/how to prevent)about it here

I remember that excellent post and the great contributions to the thread, always worth re-reading to keep the info fresh.

Hypothermia can occur even in summer, in the middle of the day if the conditions/circumstances are right. The trick is to recognise the possibility before you start to become a casualty, EddieP is quite right in his note that " education is the key to effective risk assessments." but we also need to remember that those risk assessments we make before our trip out also need to be tweaked while out to suit the local conditions, weather forecasts are often proven wrong but don't always end up in a life and death situation so we tend to just go with them blindly and hope for the best. Out at sea or up in the hills we need to up our game and not be another news headline.

Rob.

 

[nic a char]

"The trick is to recognise the possibility before you start to become a casualty" = hear hear! Or as they "say" in wastemonster "bleuagh"

 

[EddieP]

I remember that excellent post and the great contributions to the thread, always worth re-reading to keep the info fresh.

Hypothermia can occur even in summer, in the middle of the day if the conditions/circumstances are right. The trick is to recognise the possibility before you start to become a casualty, EddieP is quite right in his note that " education is the key to effective risk assessments." but we also need to remember that those risk assessments we make before our trip out also need to be tweaked while out to suit the local conditions, weather forecasts are often proven wrong but don't always end up in a life and death situation so we tend to just go with them blindly and hope for the best. Out at sea or up in the hills we need to up our game and not be another news headline.

Rob.

I should have mentioned ongoing dynamic risk assesment too.

 

[woodsorrel]

Hypothermia is a mean one.
I wrote a bit (signs/effects/how to prevent)about it here

I enjoyed reading that. Thanks!

- Woodsorrel

 

[Klenchblaize]

Hypothermia is a mean one.
I wrote a bit (signs/effects/how to prevent)about it here

Informative read but for me a pertinent reminder care of one key word: "Immobile".

When I was younger I could snug-up against a tree and wait for a fox to appear for 4 plus hours on a November afternoon/evening. I cannot do that now at 58 and probably shouldn't have at 30.

Thanks

K

 

[Robson Valley]

It's your "thermal budget" that's at stake. Whatever dry insulation you may have must be better that your ability to make body heat for a constant core temperature.
Two things go wrong when you get wet:
1. You can kisss the insulation value good-bye.
2. Water is unusual in the amount of heat energy that it can absorb with little change in temperature = cold clothes stay cold. Whatever does evaporate
carries away a ranson in body heat energy.
As a result, your bod keeps producing heat which is quickly transferred to the cold wet clothing. Now your peripheral blood circulation temperature
is cooling. Beyond some point, if that cold peripheral blood goes into your core, the shock can stop your heart.
Dr. John Hayward, hypothermic research specialist, University of Victoria, BC, Canada.

 

[EddieP]

Isn't it the hypokalaemia that does it?

 

[Robson Valley]

Possibly so. Just ahead of that, the lowered blood temperature is instigating a phase change in the membrane phospholipids which impairs transport proteins.
Even if you thought to give yourself a K-shot, the transport mechanism is so sluggish that it won't help.

Melting snow on her clothing cost her approx 76 cal/g (Heat of Fusion). As that water warmed up, it cost her 1 cal/g, a higher Specific Heat than any other substance.
For any evaporation, it cost her 540 cal/g. Humans don't release enough body heat to match that.

I've not spoken to Dr. J. in a very long time. Much of the world's supply of survival clothing and suits (Mustang) originated from research in his lab.

 

[santaman2000]

Now that makes sense. At normal everyday temperatures a normally fit person would just shiver themselves warm (and dry) if they can find shelter. ....
M

In the early 1990s two students going through the Army Ranger training here at Campo Rudder died of hypothermia. The temperature that night was in the upper 40s tp lower 50s Fahrenheit (only a bit lower than that 15C mark) Obviously they were young (ish) and healthy. In the negative column it has to be said that the training involved severe sleep deprivation and food deficit so they weren't at their peak.

But also to the point, they didn't have ready access to a shelter out in the Yellow River Swamp; and the hiker likely didn't recognize the danger/need once her reasoning was impaired.

 

[mrcharly]

Her clothing sounds adequate for the temperatures and dry weather.

It didn't cope with the wet. Did she plan a short hike and the weather changed? Once you get cold, it can be really hard to move quickly.

Also, what Klenchblaize is very applicable. When in my 20s, I could have got chilled to the bone, then run it off it off until steaming hot. Now, pushing 50, there is no way I could do that. Did this poor lady just underestimate how much her age affected her ability to cope?

 

[bigbear]

In terms of recognising hypothermia in others, one of the most memorable things I have been told was by a very experienced guide on my ML training.
His point was that yes, someone stumbling and not making sense is a sign of hypothermia, and at that stage chances are you are putting them in a survival shelter or bag with a couple of other folk and waiting for rescue. In other words it is an incident. His tip was face colour, as soon as someone in your group starts looking pale, get them to add a layer and eat something. That way you hope to avoid getting to the "stumbling over own feet and talking rubbish" stage.
I do this whenever I amleading or trainingba group, and explain why at each stop I am giving them all a good long stare.
As noted above, much harder to spot in yourself.

 

[woodsorrel]

Her clothing sounds adequate for the temperatures and dry weather.

It didn't cope with the wet. Did she plan a short hike and the weather changed? ...[/COLOR]

My thoughts mirror mrcharly's. While it's difficult to be certain without first-hand knowledge, often the simplest explanation is best. A fit, older UL hiker went trekking alone in winter conditions and ended up in an unfortunate situation with little gear to fall back on.

- Woodsorrel

 

[SGL70]

From where I am sitting (in a sofa, far, far away) I am guessing she was lacking knowledge. In a way, you don't need that much..."the ability to keep dry, warm, fed and hydrated" will go a long way. There is more to it, naturally, but as basic advice it is good IMHO.

Cheers,
Greger

 

[bearbait]

I read somewhere that a test for hypothermia is to try to touch the thumb + forefinger together on the same hand when feeling cold. If you/they struggle to do that you are much colder than you think and need to do something pronto to get and remain warm.

Mors Kochanski says "thumb and little finger" in one of his Basic Wilderness Survival Guides (In Cold, Lacking Snow).

He also indicates that wind is the part of the hypothermia equation to be most aware of. (My paraphrasing.)