Four years ago, I stood on Hoover Dam staring down at the receding water line as Lake Mead set what was, at the time, a record low:

If you blow this picture up enough, you can probably see pixels of rock that have not been exposed since the 1930s. Or maybe not. The surface elevation of Lake Mead hit 1083.18 feet above sea level today between 11 a.m. and noon Pacific time today, when this picture was taken. That is below the previous low – 1083.19 – on April 26, 1956. We can now unequivocally say that the drought of the ’00s and continued water consumption by downstream users has lowered the mighty reservoir to the lowest level it has seen since it was filled in the 1930s.

We’re about to do this again. In April, the surface elevation of Lake Mead dropped below the level for April 2010, and with each successive day, we set a new record for this point in the water year. By some time next month, Mead is forecast to drop below the 2010 record of 1081.85, set Nov. 27, 2010. I like to make graphs to help me visualize data:



