Pineapple express

Pineapple Express is a non-technical term for a meteorological phenomenon characterized by a strong and persistent flow of atmospheric moisture and associated with heavy precipitation from the waters adjacent to the Hawaiian Islands and extending to any location along the Pacific coast of North America. A Pineapple Express is an example of an atmospheric river, which is a more general term for such narrow corridors of enhanced water vapor transport at mid-latitudes around the world.

Characteristics

A Pineapple Express is driven by a strong, persistent cyclone in the vicinity of Hawaii, and an anticyclone located near the U.S. West Coast. These systems combine to produce a strong, continuous flow of moisture into the Pacific Northwest, causing heavy, persistent rain along the western coast of North America from California to British Columbia.

The Pineapple Express is so named because it brings tropical moisture and air from the vicinity of Hawaii (home to many pineapple plantations) to the Pacific Northwest. The term was first used in the 1960s by West Coast meteorologists.

Impacts

While the Pineapple Express can bring beneficial rain to areas suffering from drought, it can also lead to extreme rainfall amounts that can trigger floods, landslides, and other types of severe weather. In particular, the mountainous regions of the West Coast can receive several feet of snow from a single Pineapple Express event.

See also

• Atmospheric river
• Cyclone
• Anticyclone
• Pacific Northwest