The annual insanity hosted by my local dive store (LDS) took place over the last weekend. Every year around this time of the year (early to mid February), the LDS holds an Ice Diving class. The spring fed lake that we use is ideal for the class since the water is fairly clear and within easy reach of store.
This year, the ice was the thickest that I have seen. The crystal clear ice was around two foot thick. The way that the holes are made is interesting. Ice augers are used to drill six inch diameter holes into the ice. The holes are drilled in the shape of a equilateral triangle. Chain saws are then used to cut the ice between the holes. The end result is a hole in the shape of a triangle.
The way we conduct the ice diving is to tether three divers to a safety line. On each dive we have an instructor and two students. The class consists of various activities, but to get the certification, students have to complete three ice dives. On the second and third dives, each student gets the opportunity to be the lead diver. On the first dive, the instructor is the lead diver.
This year we had an eclectic mix of divers participating in our ice diving event from all over the country. It is always fun to have visitors from other states visit us - especially from those that come from the warm weather states. For some reason when you tell some folks that it is cold here they do not totally grasp the idea of how cold zero Fahrenheit is (before wind chill etc.). Fortunately, most of the people who were here we adequately dressed.
The weekend before, we had temperatures below zero with wicked wind chills. Fortunately for the ice diving event the temperatures were moderate. Some years we luck out. I remember one year when the actual air temperature was minus five. When I completed my dive, my hair and face were still a little wet from the water, and when I left the tent to get changed, my hair froze. That made for an excellent photo.
One of the minor annoyances of the weather forecasters and newspapers here is that they like to dramatize the weather. I suppose it is good for ratings. They never fail to accentuate the wind chills. "It is going to be minus 30 to 40 tomorrow so bundle up" they would proclaim on the evening news. But then they would say that would be the wind chill temperature, and the actual temperature will be say minus 15. Ok, I know I am splitting hairs, but can't the weather people treat us like adults and just tell us the actual temperature?
Living here everyone, and I mean everyone, knows how to dress for the weather and wind. For example, it is around zero Fahrenheit today, and here at the coffee shop where I am writing this post, there are people here with light coats and even one person with shorts on (however, I think he might need some therapy). The secret to keeping warm is layering. Everyone here wears at least three layers of clothes on the really cold days. The other thing is that the human body is wonderful at adapting to the conditions. I guess we just get used to the cold living here. You just learn to deal with it. Today I am just wearing a light fleece jacket and jeans. I am just so tired of the heavy coats, gloves and hats. However over the weekend I was completely bundled up with many layers or clothes (fleece and down jackets), since I knew that I was going to be outdoors all day.
One of the interesting features of the water temperature is that at the surface the temperature is around 33 or so. At the bottom of the lake the temperature was around 36 to 37 over the weekend. The unexpected thing is that the water is warmer at depth than at the surface. Of course this makes sense when you think about it in terms of the air temperature, but things that people are surprised by is that the water temperature is warmer than the air temperature by a fair margin. So theoretically if they are comfortable in zero degree Fahrenheit then they should be ok in 37 degree water. This idea seems to calm the students a little.
Thinking back to my first ice dive, I am reminded about how happy and surprised I was that the equipment (dry suit, thermal underwear etc.), actually kept me warm and safe. I think the most
important lesson for me was to trust in the equipment.
There is an entry on Wikipedia about ice diving for those who would like to learn more about it.
For some more pictures take a look at this site. Note the picture with the radials that point to the hole.
There is a 484 page book on Google Books called Ice Diving Operations with more information that you probably need.
Link to the PADI ice diving specialty class information.