Pineapple Express (also, Pineapple Connection) is a non-technical, shorthand term popular in the news media for a meteorological phenomenon which is characterized by a strong and persistent flow of atmospheric moisture and associated heavy rainfall from the waters adjacent to the Hawaiian Islands and extending to any location along the Pacific coast of North America. The Hawaiian Islands, once known as the Sandwich Islands, form an Archipelago of 19 Islands and Atolls numerous smaller The Pineapple Express is driven by a strong, southern branch of the Polar jetstream and is usually marked by the presence of a surface frontal boundary which is typically either slow or stationary, with waves of low pressure traveling along its axis. Jet streams are fast flowing relatively narrow air currents found at the Tropopause, the transition between the Troposphere (where temperature decreases A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena. Each of these low pressure systems brings enhanced rainfall.
The conditions are often created by the Madden-Julian oscillation, an equatorial rainfall pattern which feeds its moisture into this pattern. They are also present during an El Niño episode. El Niño-Southern Oscillation ( ENSO; commonly referred to as simply El Niño) is a global coupled ocean-atmosphere phenomenon
The combination of moisture-laden air, atmospheric dynamics, and orographic enhancement resulting from the passage of this air over the mountain ranges of the West Coast causes some of the most torrential rains to occur in the region. Orography is the average height of land measured in geopotential meters, over a certain domain Rain is Liquid precipitation. On Earth it is the condensation of atmospheric Water vapor into drops heavy enough to fall often making it to Many Pineapple Express events follow or occur simultaneously with major arctic troughs in the Northwestern United States, often leading to major snowmelt flooding with warm, tropical rains falling on frozen, snow laden ground. Examples of this are the December 1964 Pacific Northwest flood and the Willamette Valley Flood of 1996. The Willamette Valley Flood of 1996 was part of a larger series of Floods in the Pacific Northwest of the United States which took place between late January
A Pineapple Express battered Southern California from January 7 through January 11, 2005. Southern California, or So Cal, is defined as the southern portion of the U Events 1325 - Alfonso IV becomes King of Portugal. 1558 - France takes Calais, the last continental Events 1055 - Theodora is crowned Empress of the Byzantine Empire. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. This storm was the biggest to hit Southern California since the El Niño of 1998. El Niño-Southern Oscillation ( ENSO; commonly referred to as simply El Niño) is a global coupled ocean-atmosphere phenomenon  The storm caused mud slides and flooding, with one desert location just north of Morongo Valley receiving about 9 inches of rain, and some locations on south and southwest-facing mountain slopes receiving spectacular totals: San Marcos Pass, in Santa Barbara County, received 24. A flood is an overflow of an expanse of water that submerges land a deluge Morongo Valley is a Census-designated place (CDP in San Bernardino County, California, United States. San Marcos Pass (el 2225 ft / 678 m is a Mountain pass in the Santa Ynez Mountains in California. Santa Barbara County is a County located on the Pacific coast of the southern portion of the U 57 inches (624 mm), and Opid's Camp in the San Gabriel Mountains of Los Angeles County was deluged with 31. The San Gabriel Mountains are located in northern Los Angeles County and western San Bernardino County California, USA. Los Angeles County is a county in California and is by far the most populous county in the United States. 61 inches (803 mm) of rain in the five day period.
The unusually intense rain storms that hit south-central Alaska in August of 2006 were termed "Pineapple Express" rains locally.
The Puget Sound region from Olympia, Washington to Vancouver, BC received several inches of rain per day in November 2006 from a series of successive Pineapple Express storms that caused massive flooding in all major regional rivers and mudslides which closed the mountain passes. The Stillaguamish River is a river in northwest Washington in the United States. Puget Sound (ˈpjuːʤᵻt is an arm of the Pacific Ocean, connected to the rest of the Pacific by the Strait of Juan de Fuca, in the Pacific Northwest Olympia is the Capital of Washington and is the County seat of Thurston County. Vancouver (vænˈkuːvɚ is a coastal Winter storms of 2006–2007 profiles the major winter storms including blizzards ice storms and other winter events that occurred from July 1, 2006 to June These storms included heavy winds which are not usually associated with the phenomenon. Regional dams opened their spillways to 100% as they had reached full capacity due to rain and snowmelt. Officials referred to the storm system as "the worst in a decade" on November 8, 2006. Events 1519 - Hernán Cortés enters Tenochtitlán and Aztec ruler Moctezuma welcomes him with great a Celebration Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Portions of Oregon were also affected, including over 14 inches (350 mm) in one day at Lee's Camp in the Coast Range, while the normally arid and sheltered Interior of British Columbia received heavy coastal-style rains.
In British Columbia especially, Pineapple Express systems typically generate heavy snowfall in the mountains and Interior Plateau, which often melts rapidly because of the warming effect of the system. After being drained of their moisture, the tropical air masses reach the Canadian Prairies as a Chinook wind or simply "a Chinook", a term which is also synonymous on the Coast with the Pineapple Express. Chinook winds, often just called chinooks commonly refers to Foehn winds ref> in the interior West of North America, where the Canadian Prairies and
The San Francisco Bay Area is another locale along the Pacific Coast which is occasionally affected by a Pineapple Express. The San Francisco Bay Area, commonly known as the Bay Area, or the Bay, is a geographically and ethnically diverse metropolitan region that surrounds the When it visits, the heavy, persistent rainfall typically causes flooding of local streams as well as urban flooding. In the decades before about 1980, the local term for a Pineapple Express was "Hawaiian Storm".  During the second week of January, 1952, a series of "Hawaiian" storms swept into Central California, causing widespread flooding around the Bay Area. The same storms brought a blizzard of heavy, wet snow to the Sierra Nevada Mountains, notoriously stranding the streamliner City of San Francisco on January 13. The Sierra Nevada ( Spanish for "Snowy Range" is a Mountain range located in the U The City of San Francisco was a streamlined Passenger train operated jointly by the Chicago and North Western Railway, the Southern Pacific Railroad Events 532 - Nika riots in Constantinople. 888 - Odo Count of Paris becomes King of the Franks The greatest flooding in Northern California since the 1800s occurred in 1955 as a result of a series of Hawaiian storms, with the greatest damage in the Sacramento Valley around Yuba City. The Sacramento Valley is the portion of the California Central Valley that lies to the north of the San Joaquin-Sacramento Delta in the U Yuba City is a Northern California city founded in 1849 It is the County seat of Sutter County, California, United States