Things often get wild when the pineapple express visits the west coast; this time, massive mudslides buried homes and a tornado touched down outside Los Angeles. Leading meteorologists say there’s more to the recent weather than meets the eye, and NASA says there’s more rain on the way.
— NASA (@NASA) December 13, 2014
While not always scary, pineapple express storms can cause serious damage when they arrive in California after extended periods of drought, especially when they stall. The heavy rainfall they bring with them provides between thirty and fifty percent of the West Coast’s annual precipitation, but it can lead to major problems including mudslides and downed trees, plus flooding that often causes road closures and travel delays.
While the term “pineapple express” is being used to describe the storm that pounded the West Coast over the last several days, Fox’s AccuWeather.com expert meteorologist, Bernie Rayno, says that this storm doesn’t really qualify.
“Pineapple expresses are not known for wind, they’re known for rain.”
In classic cases of pineapple express, tropical moisture serves as the main source of rain. This time around, satellite images showed some dry air around Hawaii, meaning most of the precipitation was fueled by a very strong west-to-east jetstream running across the north-central part of the Pacific Ocean. Rayno said that “if this was a true pineapple connection, rainfall amounts would be double what we’re seeing now.” Even so, many news outlets continue using the terminology.
— The Weather Channel (@weatherchannel) December 11, 2014
Just what kind of storm was it that killed two in Oregon, then hit California’s Bay Area before smacking full force into Los Angeles Friday, if it wasn’t a true pineapple express? According to the Weather Channel, it was an atmospheric river– a narrow corridor of highly concentrated moisture that flows through the atmosphere.
Atmospheric river known as #PineappleExpress will bring rain/mtn #snow to West Coast, what is an atmospheric river? pic.twitter.com/jn2IXM1fr0 — The Weather Channel (@weatherchannel) December 10, 2014
A typical atmospheric river is several thousand miles long, and is capable of carrying more water at one time than is present in the Amazon, earth’s largest river. Believe it or not, there are usually between three and five atmospheric rivers present over each of the planet’s hemispheres at any given time. While the pineapple express is a type of atmospheric river phenomenon, it’s one that normally brings lower winds along with it. This time, the usually benign pineapple express brought high winds, including gale-force gusts that prompted the National Weather Service to warn Californians to be on the lookout for tornados. During the storm’s rampage through southern California, a water spout was seen over the ocean in the area of Los Angeles International Airport and an EF-0 tornado touched down just outside L.A.
— The Weather Channel (@weatherchannel) December 13, 2014
People all along the west coast are cleaning up after their visit from a pineapple express-type storm so severe that it left roads impassable, and caused widespread power outages. Multiple homes were damaged, with KTLA reporting that heavy rainfall led to fast-moving mudslides that left homes in the Camarillo Springs community north of Los Angeles up to their rooflines in mounds of mud and boulders.
Despite the damage, some Californians were thrilled to receive a long-awaited visit from the pineapple express and look forward to the next wave. After years of drought, Maury Roos, of the California state Department of Water Resources says:
“It’s a nice start.”
Image courtesy of mynextfone.co.uk