Knowledge Nugget: How is ‘Pineapple Express’ Relevant to the UPSC Exam?

Knowledge Nugget: Pineapple Express

Subject: Geography

(Relevance: Geographical phenomena are an important portion of the UPSC syllabus. UPSC has antecedently asked questions connected specified topics. Therefore, knowing the ‘Pineapple Express’ is indispensable for your upcoming UPSC CSE Prelims.)

Why successful the news?

Following an unusually adust January, a almighty atmospheric stream known arsenic the ‘Pineapple Express’ has been sweeping done bluish and cardinal California, bringing periods of beardown winds, dense rain, and snowfall successful the hills. It is expected that by Wednesday, the tempest volition weaken, perchance bringing lighter rainfall to confederate California, including Los Angeles.

Key Takeaways :

The Pineapple Express is simply a constrictive portion of atmospheric moisture that builds up successful the tropical Pacific.-National Oceanic and Atmospheric Administration (NOAA)

1. As per a study by BBC, the Pineapple Express is simply a benignant of atmospheric river— a narrow, fast-moving “river successful the sky” that transports important moisture implicit agelong distances. The lukewarm aerial and precocious humidity it carries from the Pacific pb to dense rainfall erstwhile the strategy reaches land.

2. Pineapple Express gets its sanction from the warm, moist aerial drawn into the system, originating adjacent Hawaii, a portion known for its pineapple production.

3. The NOAA explains that atmospheric rivers are long, constrictive bands successful the ambiance that transport immense amounts of h2o vapour from the tropics. Their size and spot tin disagree significantly, but connected average, they transportation a measurement comparable to the travel of the Mississippi River astatine its mouth. Exceptionally beardown atmospheric rivers tin transport up to 15 times that amount.

4. When atmospheric rivers marque landfall, they typically merchandise this moisture arsenic rainfall oregon snow, often covering a immense portion arsenic they determination inland.

5. According to NOAA, these rivers are portion of the Earth’s water h2o cycle, and are tied intimately to some h2o proviso and flood risks. While atmospheric rivers tin bring dense rainfall that whitethorn pb to flooding, they besides play a beneficial relation successful expanding snowpack.

Is the “Pineapple Express” a communal upwind phenomenon?

1. The atmospheric rivers successful the entity hap often connected the West Coast but tin hap successful different locations, including the eastbound United States, wherever they often transmission moisture from the Caribbean.

2. When this moisture begins to interact with land, it tin autumn arsenic rainfall oregon snow. Although atmospheric rivers travel successful antithetic shapes and sizes, for 1 to beryllium a “true Pineapple Express,” determination matters. The process end, wherever the moisture is pulled into the atmosphere, indispensable commencement adjacent Hawaii. Then the stream indispensable agelong continuously done the ambiance to the US West Coast.

3. Scientists pass that clime alteration whitethorn intensify these systems successful the future, expanding lower-elevation rainfall, flooding risks, and tempest severity.

BEYOND THE NUGGET: Polar Vortex  and Santa Ana Winds

1. The polar vortex is simply a ample country of debased unit and acold aerial that rotates astir some of the Earth’s polar regions. There are 2 types of polar vortex: the tropospheric polar vortex and the stratospheric polar vortex.

A pedestrian crosses a thoroughfare with the US Capitol gathering successful distance, arsenic a wintertime tempest that brought snow, crystal and freezing temperatures to a wide swath of the US arrived successful Washington, US connected January 6, 2025. (Photo: Reuters)

2. The tropospheric polar vortex occurs successful the lowest furniture of the atmosphere, extending from the aboveground up to astir 10 to 15 kilometers high. This is wherever astir upwind phenomena instrumentality place.

3. The stratospheric polar vortex exists astatine altitudes of astir 15 to 50 kilometers. Unlike the tropospheric polar vortex, the stratospheric mentation disappears during the summertime and is strongest during the autumn.

Santa Ana Winds

1. Santa Ana winds are a earthy portion of California’s clime signifier and usually stroke from October to January. These winds stroke erstwhile precocious unit builds implicit the Great Basin (region located betwixt the Rocky Mountains and the Sierra Nevada) portion a low-pressure strategy develops implicit California’s coast.

2. The quality successful unit creates beardown winds that stroke from the inland deserts of the Basin toward the eastbound and northbound of Southern California, yet moving towards the Pacific Ocean.

3. As the upwind comes down the mountains, it compresses and heats up, and its humidity falls — sometimes to little than 10%.

(Sources: What is Pineapple Express, an atmospheric ‘river’ acceptable to bring dense rains to California, Santa Ana Winds, oceanservice.noaa.gov, Winter tempest successful the US: How is the polar vortex liable for it?)

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