This graphic shows just how little water the West has left

The American West, not just California, is experiencing a long-term drought.

As drought conditions drag on, the region's water reservoirs are getting drained.

Dean Farrell of the University of North Carolina Chapel Hill made a stunning (and frightening) interactive graphic illustrating how empty the West's water reservoirs are becoming. The reservoirs at less than 50% of their capacity are represented by the red dots in this map (the larger the dot, the bigger the reservoir):

The huge red dot straddling the Utah and Arizona border is Lake Powell, which was 45.4% full in May. The other big red dot at the southern tip of Nevada, Lake Mead, was only 37.6% full.

On Farrell's website you can click reservoirs and see how their water level has changed over time.

Take, for example, Trinity Lake, California's third-largest reservoir, which has been low since the summer of 2014.

Trinity Lake's water level has fluctuated pretty wildly, presumably because of scheduled water releases, Farrell says.

But you can clearly see a major dip from 2008 to 2010, and water levels haven't recovered from their tumble in 2013:

In May, Trinity Lake was only 41.8% full, coming down from a peak of 48.4% in March after heavy December rains recharged it.

Overall, in May California's reservoirs were at only 46% of their full capacity, and 72% of their historical average.

Surface water reservoirs aren't the only source of water in the West - people also take water from underground aquifers, rivers, and desalination plants - but as they dwindle less and less water is available for people to use.

Check out and play with the graphic on Dean Farrell's website.