Man-made lakes supplying water to millions in the West expected to shrink to historic lows

In this July 28, 2014, file photo, lightning strikes over Lake Mead near Hoover Dam that impounds Colorado River water at the Lake Mead National Recreation Area in Arizona. The Bureau of Reclamation is forecasting first-ever water shortages because of falling levels at Lake Mead and says the reservoir could drop so low that it might not be able to generate electricity at Hoover Dam. (AP Photo/John Locher, File)