Sunday, May 10, 2015

Western U.S. Snowmelt Streamflow Has Already Occurred

As we all know, much of the western U.S. has been in extreme drought for several years. This year's incredibly low snowpack is going to make it even worse. The snowpack works by storing water in the mountains during the winter, then slowly releasing it during the spring and summer to provide water during the dry season. But, not this year. The snowpack is already gone in most of the west and the streamflow has already occurred. Now, there will be no flow during the hot, dry summer months that are about to start. Try to imagine what the headlines are going to look like this summer.

Lake Mead reached the lowest level ever recorded at the end of April - 1079.03 feet. If it falls below 1075 feet by January 1, mandatory water restrictions will be put into effect. The lake level has fallen 132 feet since 1998.

The drought itself is not believed (at this time) to be anything really out of the unusual. What is different is our ability to change things. We have changed the land use, but most importantly, we have changed the climate. The temperature is higher, which means mountain precipitation is falling as rain instead of snow. The snow line gets higher every year, so even the places that do get snow are getting less. And, the higher temperatures mean there is a much higher rate of evaporation of the existing water. That leads to less water and even higher temperatures.

What was that about climate change being good for us? I didn't quite catch that.

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