Wednesday, June 20, 2012

Rocky Mountains snow pack is declining

One of the great services mountains provide is the snowpack, the great mass of seasonal snow that collects on the mountains every year. Water is stored in the snowpack during the winter and gradually melts during the spring and summer, providing water during the dry months.  A declining snowpack is therefore something of great consequence. And, that is exactly what has been happening in the Rocky Mountains. Since the 1980s the amount of snow falling on the Rockies in the winter time has been dropping, reducing the amount of water flowing out of the mountains in the summer months. There could be two main reasons for this. The amount of precipitation is declining; or the amount of precipitation falling as snow is declining while the total precipitation remains about constant.

New research using tree ring data has now shown the cause is the latter reason. The amount of precipitation isn't changing that much, but the amount of snow is declining. The researchers state they believe manmade global warming is responsible for 30-60% of the decline because the amount of decline is greater than what could have occurred as a result of natural reasons.

This only makes sense and is no surprise to me. In fact, I have stated for many years this would be a result of global warming. Precipitation that would normally be near the freezing point has now been warmed up enough to fall as rain instead of snow. A great deal of snow still falls in the Rockies, but not as much as it did just 30 years ago. A big question I have now is, how does this compare to other mountain ranges?

This study here shows the snowpack in the Cascades has declined, despite an increase in precipitation. This does not bode well.

So, if you live somewhere that relies on snowpack melt for its summer water supply, you might want to start consider what measures you are going to take.

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