What is Pineapple Express, the phenomenon behind brutal storms in California?

California is bracing for more storms in the coming weekend even as the US state reels from the effects of the previous torrential rainfalls.The series of storms that have ravaged California since Christmas last year have brought floods, strong winds, thunderstorms and also power outages.Explaining the reason behind the intense weather, the National Weather Service said last week that it was brought by a "potent Pineapple Express”.What is this phenomenon seen in California and other parts of the US West Coast? How much damage have the storms caused in the state?Let’s take a look.What is Pineapple Express?Atmospheric rivers – a part of Earth's ocean water cycle – are long, narrow regions in the atmosphere that carry most of the water vapour from the tropics to northern latitudes, as per the National Oceanic and Atmospheric Administration (NOAA). “Like rivers in the sky,” it noted."Pineapple Express" is an example of a strong atmospheric river because “moisture builds up in the tropical Pacific around Hawaii and can wallop the US and Canada's West Coasts with heavy rainfall and snow”, the NOAA said on its website.

It is named the Pineapple Express due to the storm originating in Hawaii, where pineapples are grown.

“Prevailing winds cross over warm bands of tropical water vapour to form this "river," which travels across the Pacific as part of the global conveyor belt,” as per the agency.As this moisture comes into contact with land, it brings rain or snow.When the atmospheric river reaches the West Coast, it can dump as much as five inches of rain on California in a day.Around 30 to 50 per cent of the annual precipitation on the West Coast is because of a few atmospheric river events, noted the NOAA.As seen in California, there is enough precipitation because these atmospheric rivers “provide a continuous flow of moisture”, as per New York Times (NYT)[caption id="attachment_11976882" align="alignnone" width="640"] Over half of California’s 58 counties have been declared disaster areas. AP[/caption]The NOAA said that when these atmospheric rivers contain the largest quantity of water vapour and are accompanied by strong winds, they bring heavy downpours and flooding – what is currently being seen in the western US state.ALSO READ: How California’s deadly storm is not enough to reverse the historic droughtWhat’s happening in California?As many as seven storms have hit California since the end of December and two marginally weaker ones are expected, Michael Anderson, climatologist with the Department of Water Resources, told Associated Press (AP).“The challenge is they’re storms eight and nine in the sequence and the cumulative effect is likely to cause impacts larger than the storms themselves might cause,” Anderson said.Many parts of central California have experienced over half their normal annual rainfall since 26 December, as per Reuters.At least 18 people have died in these storms and governor Gavin Newsom warned that this figure could rise.As per the National Weather Service's Weather Prediction Center, the back-to-back storms are expected to continue, marked by even more heavy rainfall next week, Reuters reported.

Gale force winds have hit powerlines in the US state.

The data from Poweroutage.us showed that 30,741 customers were out of power in California as of Thursday (12 January) afternoon.Trees have been uprooted, cars and houses submerged and roofs damaged due to relentless rains and strong winds.[caption id="attachment_11976922" align="alignnone" width="640"] Torrential rains and high winds have led to high-scale devastation in California. AP[/caption]In South San Francisco, high winds knocked out part of the roof on a large apartment building.A tree fell on a commuter bus on Tuesday in San Francisco, however, no one was injured.In Sacramento county, at least two homeless people died after trees fell on their tents.A 68-year-old woman in Mendocino County was killed by a tree that fell into her home when she was sleeping, Reuters reported.While crews are cleaning the uprooted trees across the Bay Area, more are expected to fall as downpour continues. “The soil is basically like a sponge, and at some point it can’t hold any more water and trees become essentially almost buoyant in the soil and very loose. And then you get the combinations of high winds and that’s when you get tree failures, meaning full trees uprooting and falling over," arborist Remy Hummer told AP.Deaths have also occurred due to people being stuck in inundated vehicles.A 43-year-old woman was found dead inside a car submerged in about 10 feet of floodwater in Sonoma County.Some houses in costly Los Angeles hillside areas have been ruined by mudslides, which also made some roads impassable.As per the Reuters report today, most of the evacuation orders were called off across the state but not in the rural town of Planada in Central California which remained submerged.Brian Ferguson, spokesperson for the state Office of Emergency Services, said that more than half of California’s 58 counties were declared disaster areas and the repairing work is likely to cost over $1 billion, AP reported.With inputs from agenciesRead all the Latest News, Trending News, Cricket News, Bollywood News,India News and Entertainment News here. Follow us on Facebook, Twitter and Instagram.