Last year was California’s driest year on record yet, and as of right now two-thirds of the state is still in “extreme” to “exceptional” drought conditions, according to the U.S. Drought Monitor.

What exactly is to blame? It is Earth Day after all, so it’s worth wondering if climate change is responsible. In truth, there are many complex factors that lead to droughts, and while climate change may be one of them, it’s hardly the only factor. In the case of California, the culprit is a ridge of high pressure air off the West Coast of the United States that is four miles high and two thousand miles across. The ridge has been diverting storms that form over the Pacific Ocean away from California and up to Canada.

Such phenomena are common. What makes this one so serious is that it persisted for over a year instead of a few weeks. And researchers predict we could see more of these ridges by the year’s end.

In our latest Explainer Music video, we explain how the drought started, its effects, and what the future holds for dried-out Californians:

[Video by Explainer Music and Craig Newton]