Drought in the West, Freeze in the East–a Possible Explanation

The US West Coast is suffering a catastrophic drought. The eastern half of the country has just experienced one of the worst winters ever recorded. Now scientists at think they have at least a partial answer that explains both situations: a huge mass of unusually warm water that has formed in the Pacific Ocean off the West Coast. It prevents winter storms from moving south from the arctic as they normally do, and thus there is no rain along the west coast and, most importantly, no snow in the mountains. So, is it permanent or temporary?

It was first noticed developing two years ago, but whether or not it is a temporary situation or something permanent. If it is permanent, or long-lived, catastrophic water shortages will develop along the West Coast. As the drought persists, farming will be profoundly harmed, and cities along the coast will have to resort to desalinization in order to survive with even a minimal water supply.

Presently, all models point to it continuing through the end of 2015, according to Nick Bond, a climate scientist at the University of Washington’s Joint Institute for the Study of the Atmosphere and Ocean. Bond’s study finds that the mass is being caused by a persistent high pressure ridge that has caused a calmer ocean during the past two winters, so less heat was lost to cold air overhead.

University of Washington professor of atmospheric sciences Dennis Hartmann says, "The pattern that causes the warm area has become stronger since the 1980s, and is now more dominant than either the Pacific Decadal Oscillation or the El Nino cycle. "It’s an interesting question if that’s just natural variability happening or if there’s something changing now about how the Pacific Ocean decadal variability behaves."

Bond does not believe that the situation has been caused by global warming, but warns that it will become a more characteristic feature of the Pacific Ocean as the planet continues to warm.