Pipestone RiverPosted: October 17, 2009
As I mentioned in the previous post, there are a number of conditions that must be met before we begin our snowmaking for the season. One of those conditions has now been met with the passing of October 15th – the traditional start to our snowmaking season.
Why then, you might ask, is there still no man-made snow on the mountain? That’s due to the fact that another condition of our permit – the flow level of the Pipestone River – has not been met. The Lake Louise Ski Area draws all of its water from the river, and for the snowmaking system to kick in, it must be flowing at 90% of its normal flow for that date. With a drier-than-normal August and September, there was less moisture than normal to end up in local rivers and streams. Then, with the well-below-freezing temps of the last few weeks, any available moisture was frozen in place, leaving even less.
Speaking about temperatures, that was the one necessary condition that was in place for snowmaking to start – it was cold enough to make snow. Not only that, temperatures stayed close to optimal for snowmaking, about -15C. Now that we’ve emerged from that early cold snap, we can continue hoping for wamer temps or wetter weather, or both. Today at Lake Louise, we have both, as there has been a steady rain falling all day in temperatures warm enough to begin to melt some of the snow that’s fallen in recent weeks.
Of course, nobody likes to hear about melting snow so close to opening day, but when you work in the ski industry, optimism is always welcome, and here’s my rosy take on the next few weeks. First, rain means more water in the river, which means snowmaking. Second, warm temps mean more melting, which also means more water in the river. Once the river gets back to normal levels, colder temps are inevitable, and our up-to-now silent snow guns can waken and do what they do best.
There are other benefits to our warm and rainy weather that have little to do with making snow. We’ve already had a few snow events this fall, meaning most places on the upper mountain have at least some snow, generally ranging from one or two cm’s to thirty or forty. Early snowfall isn’t a bad thing in itself, but the right things need to happen after to ensure those first layers of snow don’t deteriorate and come to haunt us for the rest of the season. In short, it needs to keep snowing regularly (even little bits are okay) and get colder gradually and not too severely. That didn’t happen obviously, and not only did it stop snowing, but the mercury dropped to new lows for this time of year, and the happiness over the early snowfall turned to concern that it wouldn’t survive this bout of Arctic weather.
Now, however, warm temps and rain are likely settling things out, and if all goes well, we may have an excellent base on our hands for the winter. At the same time, if the upper-mountain snowpack becomes too wet, it’s more likely to develop a crust, which can be more troublesome than a persistent weak layer in the snow. We haven’t yet had a chance to see how the snowpack is changing in this weather, so we’re crossing our fingers. Until then, we have an eager crew of snowmakers who are keen to ply their trade. At the first possible moments, the snow guns will roar to life, and we can get down to serious snowmaking business.
I learned some interesting tidbits about the flow of the Pipestone River the other day.
When determining whether there’s sufficient flow in the river, it all goes by date. That means that if we want to make snow on Oct 25, we must meet or exceed 90% of what is considered normal for that specific date. That number is derived from measurements on that date for the last thirty years, and can vary somewhat from day to day. Sometimes it can vary significantly from one day to the next, usually due to a sudden and extreme change in weather.
Right now, coupled with relief that there’s water being added to the river is concern that too much may be added. This may not affect us this year, but it may push up the nominal 90% figure for future years based on a higher-than-normal number being added to the formula. Of course, there’s little we can do about it!
Deep or prolonged cold snaps during the winter can also rob the river systems of water, in the form of river ice. Some forms along the river bed, which reduces the flow. Ice dams can also form upriver with the same result. These dams generally melt away with the return of warmer temps, but there have been occasions where the release of water was sudden and extreme, sending a torrent of water that has significant destructive potential.