Sea Ice Training
Here's a question. What's the most important thing you need to be able to recognize on the sea ice? Think hard!
If you said a crack - you're right! So, in class today we learned how to spot and avoid a sea ice cracks.
Factors that can affect the sea ice.
There are many factors that can affect the thickness and strength of the sea ice. These are the main ones - with a few examples of each. Can you think of any others?
- Environmental factors - such as temperature, the amount of snow cover or currents.
- Geographic factors - such as surrounding islands, coastlines or icebergs.
- Mechanical factors - such as icebreakers, large vehicles, aircraft.
My big 'take-away' during the classroom portion of my training was that during this time of year the snow hides cracks - so we really have to pay attention.
During the class, we learned 2 important things:
- How to recognize a crack
- How to profile a crack
How to recognize a crack.
In order to recognize a crack, we have to look for certain things:
- Long linear features - similar to a crack in the sidewalk. On a snowmobile, however, penguin tracks can also look like a sea ice crack. So you really have to be on the lookout!
- Changes in the snow cover - like color, texture, or reflectivity (how the snow reflects light).
- Seals - They haul out on the ice through holes and cracks in the sea ice and leave signs of their passage. So, if we see a seal, we know it there's a crack or hole somewhere! Which means our team needs to be extra careful because we are looking for seals!
How to profile a crack
- Look for signs of a crack - for example, a long linear line in the snow or seals!
Potential crack here! Let's investigate.
- If you suspect a crack, stop your snowmobile before you cross the crack.
- Probe the suspected crack with an ice probe. The probe should go through the snow and stop when it hits the top of the ice. If you feel like you are hitting solid ice - it is safe to cross.
Patrick (left) and Chris investigating the crack with a shovel and ice probe.
- If not, you may have to profile the crack and here's how you do that:
Expose the crack - Remove the top layer of snow to expose the small crack.
Corey -our sea ice instructor - showing us how to expose a crack
Drill through the ice in various places in order to find the depth of the ice. As you are drilling notice the type of ice - is it dry? moist? slushy? or wet? This tells us the different phases of ice.
Chris and Alex in the middle of the drilling process. The ice was so thick here we needed to add an extension to the drill. The drill is now taller than I am - and it's even in the hole.
Measure the thickness of the ice in several places. You do this by dropping the measuring line and tape down one of the drill holes.
Corey and Alex holding up the measuring tape and line. Notice the metal rod on the end!
If you look closely at the line, you'll see a metal rod at the end. This rod will 'catch' on the bottom of the ice when you drop it in the drill hole. Then, all you have to do is pull the measuring tape up and you know the exact thickness of the ice.
Alex measuring sea ice thickness. This spot measured 1.3 meters - well above the required thickness.
Remember, if the ice is at least 30 inches thick - it's safe to cross.
If there are drill holes that are not 30 inches deep you need to find the 'effective width' of the crack. This is the width of the crack that is less than 30 inches across. In order to cross these small cracks, the width has to be less than less than 1/3 the width of the vehicle track length. Since our group is taking snowmobiles, we can't cross a crack with an effective width that is over 20 inches - nor do we want to.
Stop... Math time! If our snowmobiles can go over small cracks (less than 20 inches) - what is the actual length of the snowmobile.
Flag the path and all potential dangers
Flagging the route. Red or green flags indicates a safe path. A black flag indicates - a potential hazard
Remember
Keep an eye out for cracks!
Probe the ice if you suspect a crack and remember the rules...
Rule #1 - Ice must be a minimum of 30 inches thick. If it is - you are safe to cross.
Rule #2 - The effective width of the crack must be less than 1/3 of the vehicle track length.
Seal sighting, Seal sighting!!
I thought you'd enjoy a picture of our first close-up seal sighting. We enjoyed her company while 'lunching' on the sea ice! They truly are magnificent creatures!
First seal sighting!