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!