I have read somewhere that you can add up the air and water temperature
to determine the degree of hypothermia hazard. What I don't remember is
the range of total temperature that was relatively safe vs. unsafe. I
did some google searching without finding what I was looking for. I did
find some survival time tables as a function of water temperature, and
one reference that said you should wear a wet suit if either the air or
water temperature is under 65 degrees F.

I am mostly a river canoe person, but I do get out on lakes from time to
time.

Yes, I know quite a bit about hypothermia, have read a lot about it,
experienced it, pulled a hypothermic swimmer out of the water (I still
tell that story 30 years later), etc. I wear a farmer john wetsuit when
I think I might swim. I do not paddle in the wintertime.

Anybody have a pointer to an article with rules of thumb?

Richard

Hey Richard,

When I started boating the rule was water+air temp should equal 100
degrees before needing extra protective gear. Some in our club claim 120
respectfully. Another thing I consider with winter boating is adding a class
number to a normal warm weather run. Ex: I consider a Class II a calss III
in winter.
Mike
"Richard Ferguson" wrote in message
...
I have read somewhere that you can add up the air and water temperature
to determine the degree of hypothermia hazard. What I don't remember is
the range of total temperature that was relatively safe vs. unsafe. I
did some google searching without finding what I was looking for. I did
find some survival time tables as a function of water temperature, and
one reference that said you should wear a wet suit if either the air or
water temperature is under 65 degrees F.

I am mostly a river canoe person, but I do get out on lakes from time to
time.

Yes, I know quite a bit about hypothermia, have read a lot about it,
experienced it, pulled a hypothermic swimmer out of the water (I still
tell that story 30 years later), etc. I wear a farmer john wetsuit when
I think I might swim. I do not paddle in the wintertime.

Anybody have a pointer to an article with rules of thumb?

Richard

Grip wrote:
Hey Richard,

When I started boating the rule was water+air temp should equal 100
degrees before needing extra protective gear.

That's one of the most dangerous "rules of thumb" out there, as there
isn't any combination of temps equaling 100 where it's safe to not wear
immersion clothing.

Some in our club claim 120 respectfully.

This level is closer to realistic, but still not enough. Any such rule
is too much of an over-simplification to be useful or safe.

Using air and/or water temperature to relate to river grades perverts the
river grading system. Dress for the water temperature on rivers. On the west
coast of Canada you can almost always see the snow that the river is coming
from. It isn't hard to figure the water temperature.

--
Sincerely,
Carey Robson -- www.CanoeBC.ca


"Grip" wrote in message
...
Hey Richard,

When I started boating the rule was water+air temp should equal 100
degrees before needing extra protective gear. Some in our club claim 120
respectfully. Another thing I consider with winter boating is adding a
class
number to a normal warm weather run. Ex: I consider a Class II a calss III
in winter.
Mike
"Richard Ferguson" wrote in
message
...
I have read somewhere that you can add up the air and water temperature
to determine the degree of hypothermia hazard. What I don't remember is
the range of total temperature that was relatively safe vs. unsafe. I
did some google searching without finding what I was looking for. I did
find some survival time tables as a function of water temperature, and
one reference that said you should wear a wet suit if either the air or
water temperature is under 65 degrees F.

I am mostly a river canoe person, but I do get out on lakes from time to
time.

Yes, I know quite a bit about hypothermia, have read a lot about it,
experienced it, pulled a hypothermic swimmer out of the water (I still
tell that story 30 years later), etc. I wear a farmer john wetsuit when
I think I might swim. I do not paddle in the wintertime.

Anybody have a pointer to an article with rules of thumb?

Richard

Carey Robson wrote:

Using air and/or water temperature to relate to river grades perverts the
river grading system. Dress for the water temperature on rivers. On the west
coast of Canada you can almost always see the snow that the river is coming
from. It isn't hard to figure the water temperature.

Yep, I agree. Paddling glacier melt rivers in the middle of the summer,
one learns that lesson very quickly! If I'm too hot, I'll roll to cool
off, if I'm too cold because I didn't wear enough for the water temp, I
might die.

--
Wilko van den Bergh wilko(a t)dse(d o t)nl
Eindhoven The Netherlands Europe
---Look at the possibilities, don't worry about the limitations.---
http://wilko.webzone.ru/

"Wilko" wrote in message
...
Carey Robson wrote:

Using air and/or water temperature to relate to river grades perverts the
river grading system. Dress for the water temperature on rivers. On the
west
coast of Canada you can almost always see the snow that the river is
coming
from. It isn't hard to figure the water temperature.

Yep, I agree. Paddling glacier melt rivers in the middle of the summer,
one learns that lesson very quickly! If I'm too hot, I'll roll to cool
off, if I'm too cold because I didn't wear enough for the water temp, I
might die.


Hmm, I'm not so certain the I agree that considering water temps perverts
the rating system, whether or not you are dressed appropriately. Ice cold
water is harder to paddle than pleasant tropical water for many reasons
(icecream headaches from face shots, hypothermia--even with appropriate
clothing, reaction time when you flip, the strength in your hands, ice crust
and other obstacles). And dressing appropriately for icy winter water is a
pretty bulky set-up, and will effectively change how you can paddle when
compared to the same rapid on a summer t-shirt and pfd day.

Besides, its already a pretty perverted system. Its supposed to define the
difficulty of the rapids, but what determines that? A rocky rapid is
harder in a breakable glass boat than in a plastic one. A beginner will find
the same rapid impossible that an expert finds simple. A raft and a kayak
will seldom agree on the difficulty of a rapid. A remote rapid with little
chance for rescue is considered harder than the exact same rapid if a road
was put in right next to it. A certain rapid is much harder in a torrential
rain with poor visibilty, or a snowstorm than on a sunny summer day. The
list goes on, and most folks have a very informal allegiance to it anyway.

Unless we want to standardize *everything*, rating systems regularly take
all sorts of variables into account, and produce all sorts of variations. To
truly have a standard system, I imagine a system that is based on assuming
all paddlers on all rivers:
a) wear appropriate clothing for whatever the current weather is and
that the particular clothing does not affect their paddling on that day.
b) are in the same type of boat ('glass, plastic, rubber, whatever)
which are the same type (raft, yak, canoe) and the same style (squirt,
downriver, playboats, slalom....)
d) have the same theoretical access/egress availability and accessiblity
for rescue
e) are being paddled by the same type of paddler (beginner,
intermediate, expert...)

etc etc.
As long as grading systems are NOT standardized for the myriad of possible
variables, then there's nothing perverse about including the restrictions of
clothing as a factor, IMHO.

--riverman

riverman wrote:
"Wilko" wrote in message
...

Carey Robson wrote:


Using air and/or water temperature to relate to river grades perverts the
river grading system. Dress for the water temperature on rivers. On the
west
coast of Canada you can almost always see the snow that the river is
coming
from. It isn't hard to figure the water temperature.

Yep, I agree. Paddling glacier melt rivers in the middle of the summer,
one learns that lesson very quickly! If I'm too hot, I'll roll to cool
off, if I'm too cold because I didn't wear enough for the water temp, I
might die.



Hmm, I'm not so certain the I agree that considering water temps perverts
the rating system, whether or not you are dressed appropriately.

I agreed with the dressing for the water temp, that's all.

I guess I should have clipped the first sentence of Carey wrote.

--
Wilko van den Bergh wilko(a t)dse(d o t)nl
Eindhoven The Netherlands Europe
---Look at the possibilities, don't worry about the limitations.---
http://wilko.webzone.ru/

Richard Ferguson wrote:
I have read somewhere that you can add up the air and water
temperature
to determine the degree of hypothermia hazard. What I don't remember
is
the range of total temperature that was relatively safe vs. unsafe.
I
did some google searching without finding what I was looking for. I
did
find some survival time tables as a function of water temperature,
and
one reference that said you should wear a wet suit if either the air
or
water temperature is under 65 degrees F.

I don't see where air temperature is really a factor for this, since it
can have a high variability and only some relation to water
temperature. You can check out some sites on Web sites at sites or
gages with air and water temperature. The two are related at times for
natural streams, especially at the extremes, for very cold and very
warm periods. But where the water temperature is effected by other
factor, glacier runoff, rain, snowmelt, and the ever-present dam
releases, the two aren't well related.

Some examples in Washington State a

http://waterdata.usgs.gov/wa/nwis/uv..._no= 12056500
http://waterdata.usgs.gov/wa/nwis/uv...te_no=12058800

The first is above a reservoir, the second below, at slightly different
elevations but not significantly for many cold days.

Interesting thought, but questionable application.

--Scott--

Scott M. Knowles "Opinions expressed are entirely my own."

Hydrologist, MS-Geography

"All things merge into one, and a river runs through it."
- Norman MacLean

"wsrphoto" wrote in message
oups.com...
Richard Ferguson wrote:
I have read somewhere that you can add up the air and water
temperature
to determine the degree of hypothermia hazard. What I don't remember
is
the range of total temperature that was relatively safe vs. unsafe.
I
did some google searching without finding what I was looking for. I
did
find some survival time tables as a function of water temperature,
and
one reference that said you should wear a wet suit if either the air
or
water temperature is under 65 degrees F.

I don't see where air temperature is really a factor for this, since it
can have a high variability and only some relation to water
temperature. You can check out some sites on Web sites at sites or
gages with air and water temperature. The two are related at times for
natural streams, especially at the extremes, for very cold and very
warm periods. But where the water temperature is effected by other
factor, glacier runoff, rain, snowmelt, and the ever-present dam
releases, the two aren't well related.

Some examples in Washington State a

http://waterdata.usgs.gov/wa/nwis/uv..._no= 12056500
http://waterdata.usgs.gov/wa/nwis/uv...te_no=12058800

The first is above a reservoir, the second below, at slightly different
elevations but not significantly for many cold days.

Interesting thought, but questionable application.

--Scott--


Hee hee. I hate when I do that.

--riverman
(PS: its not HOW the air temp affects the water temp that matters. Its how
the air and water temp affect YOU.)