6cm Overnight at Lake LouisePosted: January 17, 2011
Another 6cm of new snow fell overnight at Lake Louise, and Monday morning saw a break in the weather that’s pounded the Lake this past week. With the warmer temperatures, this new 6cm is slightly heavier than the rest of the over 50cm we’ve received lately, but should still make for great skiing.
One way to describe the heaviness of new snow is to use water equivalency. As a rule of thumb, 1mm of moisture will produce 1cm of snow. In other words, if you take 1cm of snow and melt it, the result will be 1mm of water. On colder days, the snow is lighter, which means the same 1cm of snow will melt into less than 1mm. Likewise, on warmer days, 1cm of snow may have more than 1mm of water equivalency. This was the case last night, as our 6cm of new snow has the equivalent of 8mm of water, making the snow slightly heavier than normal. It’s not a huge difference, so it’s not like there will be a thick layer of slop on top of all the light powder we received in the storm.
The surface of the snow is more likely to be affected by the steady moderate winds that have been blowing for the last thirteen or so hours. Wind moves snow around, in the process breaking apart the delicate crystals into smaller pieces. When snow falls with no wind, the crystals land gently on top of each other, and there ends up being lots of space, or “air”, around the crystals, making for soft fluffy conditions. Once the wind blows and creates the smaller broken crystal pieces, they pack tighter due to both their smaller size and from the packing motion of the wind. Slab conditions are the usual result.
With the sustained overnight winds and huge amounts of recent snowfall, avalanche control teams have their hands full today getting terrain open. Things will move a little slower, both to ensure the safety of crews and that teams are getting to all the areas they need to get to. We’re once again looking to do some heli-bombing in the next twenty-four hours or so, and that will allow us to make some great progress in stabilizing the touchy conditions.