The Western part of the U.S. has experienced wild weather this spring. Massive snowfall in the Western mountains, flooding in Hawaii and California, and wildfires throughout the Southwest may seem like an unusual weather combination, but it is all part of a weather pattern known as La Niña.

IMAGES: Wild Weather

La Niña is defined as cooler than normal sea-surface temperatures in the central and eastern tropical Pacific ocean that impact global weather patterns. La Niña conditions recur every few years and can persist for as long as two years.

La Niña impacts global and U.S. climate patterns.

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La Niña often features drier than normal conditions in the Southwest in late summer through the subsequent winter. Drier than normal conditions also typically occur in the Central Plains in the fall and in the Southeast in the winter.

In contrast, the Pacific Northwest is more likely to be wetter than normal in the late fall and early winter with the presence of a well-established La Niña. Additionally, on average La Niña winters are warmer than normal in the Southeast and colder than normal in the Northwest.

Courtesy of NOAA Public Affairs