Ismannaskap – isbedömning av sötvattenkärnis på plats


Icemanship is the art of skating on untouched and changing natural ice and continuously judging its suitability for skating. In this film I will show how I am judging unknown sweet water ice in front of me. For instance when you are standing on the shore and are about to step out on the ice or when you are on the ice meet and a boarder to a different type of ice. My toolbox for judging ice consists of five different tools An ice pole, an ice skate, an ice saw, a Vernier caliper, and my own body weight. The ice pole is the first and most important tool. I can use the ice pole without having to step out on the ice in front of me. And also, the result of using the ice pole can roughly be interpreted in the same way independent of the ice type. For instance on snow ice or salt water ice. Using the ice pole will give me good information about the strength of the ice. There are many different types of ice poles, and people are using them in different ways. What I will say now is true for me when I am using my own ice pole. If my ice poles goes completely through the ice then the ice is too weak. If my ice pole does not go completely through the ice, but reaches the water, then the ice is strong enough or just strong enough. If I do not reach the water at all, then the ice is strong with margin. I am also checking if there is an up-welling of water. In that case the ice is just strong enough. If there is no up-welling of water from the hole even if I load the ice with my body weight then the ice is stronger and you can feel more safe. Summary: by using the ice pole and checking if there is an up-welling of water on the ice or not I can make a rough estimate of the ice strength. I am also using my skates as a tool in judging the ice. By stomping with the skate on the ice you can hear a tone which will give information of the ice thickness. The darker the tone, the thicker the ice. This will be clear if we listen to a sequence of stomps on different ice thicknesses We will start with a 2.2 cm thick ice and end with a 12 cm thick ice. Often it is not the tone itself but rather a change in the tone that is most interesting. Here we will listen to a higher tone on thinner ice changes to a very dark tone on thicker ice. When I am stomping on the ice I will also check if there any cracks formed under the skate. On thicker ice there will be no cracks. but on just strong enough ice there will be a star shaped crack. On weak or too weak ice there will also be cracks in a circle. This is a strong warning sign. Sometimes I am using the ice saw to cut out a piece of ice. I will make two holes using the ice pole and then cut out a triangular shaped piece of ice. On the piece of ice I can measure the ice thickness with precision. 4,5 cm and judge the ice quality. On snow ice it is especially interesting to know how much black ice there is under the snow ice. An now: the Vernier caliper. To measure the ice thickness with the Vernier caliper on new sweet water ice will give good information about the ice strength. Ice thickness7 cm: strong with margin Note that is only true for new sweet water ice when there is minus degress in the air. At last, my body weight is also a good tool in judging the ice. When you believe that the ice is strong enough you can carefully step out on the ice. After that you can start to skate carefully. If the ice is just strong enough it will make cracking sounds and a long crack will form as a track. If there also will be perpendicular cracks in a “fish bone pattern” then the ice is very close of being too weak. To load the ice with extra weight you can skate on one skate and move your body up and down. This wooden plank I can just make reach the ground. With two more (not as heavy) bodies who are standing still will make the plank touch the ground But if we are only two the plank will not reach the ground Hence, moving your body up and down can give the same effect as the double of your own body weight. So, this was roughly the different tools I use for judging sweet water ice in front of me. Different types of ice will need other tools. And to skate on the ice a continuously judge the ice is also a different matter. That is my plan for my next “icemanship” film. I hope you have found something to use in your own ice judging technique. I will be happy for comments here on YouTube. I hope we will meet on the ice. Remember not to skate on natural ice without knowledge, tools or friends! Load the ice carefully!

24 comments

  • Mycket bra! Kan tilläggas att synen tillhör verktygen också, för att identifiera isförändringar och isgränser. Om det är snö på isen försvåras detta väsentligt, då man inte ser isytan.

  • Tack för en bra film, delar vidare till Friluftsfrämjandets ledare

  • Tack för en utmärkt film. Rappt och instruktivt gjord! Som ledare ska jag tipsa mina deltagare om filmen.

  • Mycket bra och pedagogiskt framfört

  • Du skrev "Ej bärig för istjocklek <3 cm", förvisso sant. Men det blev ett glapp mellan 3-4, så föreslår du ändrar i tabellen till "Ej bärig för istjocklek <4 cm".

  • Mkt bra och nyanserad information om ett komplext område! Ser fram emot att se fler filmer!

  • Tack för en utmärkt instruktionsfilm. Fina exempel. Den blir utmärkt i isrävskursen.

  • Intressant – ser fram emot nästa film!

  • Pedagogiskt och genomarbetat.
    Gick inte att kommentera när jag tittade i mobilen så här kommer en kommenterar från PC i stället.
    Bengts kommentar om synen håller jag med om speciellt användbart är att kombinera olika sätt. T ex så gungar jag ofta ordentligt och ser hur isen eller små vågor guppar där den är tunn eller bara lösa flak en bit bort t ex intill vassen eller vid ett strömställe. Att isen ger efter när man gungar eller åker är också en varningssignal som man kan uppleva innan man får ljudindikation.

  • SO helpful and very well done, thank you! I am looking forward to seeing the next videos you create on this topic, so I have subscribed to your channel.

  • Enkelt och tydligt! Tack!!

  • Fox Family Heating and Air Conditioning

    Wonderful video. Thank you for taking the time to do this. Very well put together.

  • Mycket sevärd film om hur enkla hjälpmedel bidrar till en säkrare bedömning. Mycket pedagogiskt upplagt med stor research. Tar särskilt till mig sekvensen om ljudklangen och skall blir mer ett med min pik så jag kan bedöma utifrån min slagkraft. TACK, och ser fram emot nästa film.

  • Great video! Do you attach extra weight on your ice pole? It looks taped on…how much is the weight?

  • Mad River Boat Trips

    Great Video very well done! Thanks for the English Subtitles for those of us not fortunate enough to speak Norwegian.

  • Robert Lombardo

    Very helpfull techniques for ice skating safety. I have been using the "sounding" method a lot this season using one skate tapping on the ice as I skate. Thanks

  • Excellent, thanks a lot for posting this. Hope you do some on old ice.

  • Great video, very well done, and thank you a lot for the subtitles. I am a total coward on ice, which is not necessarily a bad thing, but sometimes it means that I do not get out the whole season being afraid the ice is too thin.

  • Mycket instruktivt och bra. I fortsättningen kommer jag att ta med mitt munspel när jag ska ut på isen (pianon är ju lite otympliga).

  • Thank you for sharing your knowledge. I love my ice poles. It is good to know what the ice pole penetrations mean. This link is also very helpful: http://lakeice.squarespace.com/testing-tools/

  • Tack! Mycket pedagogiskt! Ser med stort intresse fram mot nästa kunskapsfilm:)

  • Stijn Van de Velde

    Takk for denne gode instruksjonsfilmen. Jeg lurte på hvilket utstyr du har teipet til den øvre delen av staven?

  • Tämligen fantastiskt tydlig och pedagogisk, fina jämnförelser i ljud.

  • Bästa och mest lärorika jag sett just om bedömning av isens bärighet, tack 👏

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