Water temperature

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  • #20868
    Nick Heath

    Questions arose at Monday’s meeting on the topic of ocean water temperatures, in relation to cold water shock and hypothermia in local waters.

    It seems that there are abundant data, although it isn’t quite clear to me how the measurements are taken i.e. at what depth.  Assuming these are surface (or near-to-surface) temperatures, here is what the web site http://www.seatemperatureinfo.com shows for today:

    Ucluelet 7.8 C (annual mean range is about 8 C winter to 13 C in summer)

    Interestingly, the Strait of Georgia is slightly colder in winter, presumably due to runoff and less influence from warm currents, but gets quite warm in summer, especially where flushing is minimal, like in Desolation Sd.

    Hornby Island 7.4 C (annual mean range is about 7 C winter to 17 C in summer with occasional days reaching over 20 C.)

    I’ve measured 22 C at the surface in summer in Howe Sd.

    So most of the year, but not necessarily every day in July & August , you should be wearing your thermal protection.

    In addition, I’ve noticed how much colder than our ocean are local lakes and rivers. Brrr.

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  • #20925
    Nick Heath

    I guess that threshold depends on how long you will be immersed, which will vary from a few minutes to many hours if you are unfortunate enough to fall into the water miles from shore and lose contact with your boat to high winds, and no-one notices, as has happened all too often.

    There are tables compiled that relate time immersed at a specific water temperature to loss of consciousness & death but I haven’t accessed them recently. (As I understand, some of the early work was highly unethical Nazi experimentation on unwilling concentration camp captives, so is uncited in the literature).

    Mike’s advice seems spot on!  Don’t bother to work out if you don’t actually need thermal protection around here – normally you need it!

    Mike McHolm

    Hi Nick,
    Thanks for the info. I think the link is a dot info not a dot com: https://seatemperature.info

    P.S. My two cents; I teach up to Skills L-2 at Jericho Beach Kayak and I generally wear my dry suit year round with merino wool base layers (top and bottom), wool socks, synthetic t-shirt, nylon pants and neoprene gloves. This works for immersion in winter and summer. If I get cold in the winter I’ll add a thin jacket. In summer I spend a lot of time in the water, either standing up to my waist or chest teaching rolling, rolling myself for practice or to cool off, and demonstrating solo re-entries. On really hot days I’ll go with a “farmer john” wet suit. I always keep a neoprene beanie in my pfd. You can put one on cold and wet and within 5-10 seconds your head will be warm. Goes a long way for comfort in cold conditions and can help prevent hypothermia.

    Long story short, my motto is dress for the water first and weather second. Always look up water temperature as part of your trip planning. Always carry a complete change of clothes and bivy sack in a dry bag on all outings.

    Roland Stefani

    You suggest thermal protection for most days.   Is there any  generally accepted threshold temperature below which thermal protection is recommended?

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