Weather Whisperer

Pineapple Express

Evelyn Browing Garriss and James J. Garriss

An explosive grenade is nicknamed a pineapple. A recent storm that clobbered California is nicknamed the Pineapple Express and it has been just as explosive.

The innocent sounding name comes from the type of wind that lofts up from the tropics to the West Coast. In the day of sailing vessels, it helped speed the voyage from Hawaii to Seattle, thus the name Pineapple Express. Of course, sometimes when the warm moist air hit the cool continental land mass, it would precipitate out in heavy rains, but Seattle was used to rains.

December’s Express was more than a Northwest drizzle. The Pacific Ocean was in the middle of a strong La Niña. This meant the Tropical Pacific and waters off the American coastlines were cooler than normal. Meanwhile the Western Pacific was unusually warm. West Pacific tropical disturbances were stronger and they could travel further north and east. When they neared North America, they hit the winter-cooled land and created a deluge.

Then the unexpected happened. The Arctic Oscillation has been strongly negative and has pushed a lot of US weather patterns further south than usual. (Just ask frozen Florida!) The Pineapple Express that normally sails happily to Seattle instead was steered south where it hosed down California.

This photo, taken by NASA satellite, shows the “pineapple express” storm that brought heavy rain to Southern California.

The results were stunning. For over a week California was hit by record-breaking storm after storm. Hillsides were hit with between 12 – 24 inches of rain, while one mountain sensor, Pascoes snotel, reported 17 feet of snow. From California, through Nevada, Utah, Colorado and Wyoming, regions reported up to 800% of their normal precipitation in that period. (See chart below. Credit: NOAA)

There were floods, landslides and avalanches, but not all results were bad. Reservoirs have been filled, Western snow packs are restored and California’s drought has nearly ended. Northern California is even reporting a resurgence in the number of returning salmon.

Most experts expect the Express to return to its normal Northwest route and California to return its normal dry La Niña weather. But it has been a pretty spectacular explosion for a wandering pineapple.

Have you ever “ridden” the Pineapple Express? Do we have any California fans? If you’d like to share your thoughts, I’d love to hear from you. (Just post comment below.)


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Pineapple Express

Here all this time I thought the Pineapple Express was a front that blew in from Hawaii. Kinda thought it was a might cool to have come from there.

"Pineapple Express"

WHY can't So Cal realize that if they had more resavoirs to catch this rain and run off that maybe they wouldn't need so much of N Ca's water from the ranchers and farmers that produce food for them? Every year they get fires and floods...duh


Most weather people only tell what the weather will be. It makes so much more sense when you (I!) know why. Thank you for this easy-to-understand explanation.

Great background information on why it rained in CA!

A really good explanation on The Pineapple Express and the havoc it caused, plus some of the benefits that accrued as a result. Very informative and well presented.

Not all of California received the rain

I live just south of San Jose. While we received a couple of inches of rain, we didn't experience anything like they did in southern California. I LOVE THE RAIN and hope the Pineapple Express stays around a bit longer. I'm not quite ready for spring.

Great explanation!

Thank you for explaining this so well....thoroughly enjoyed reading it!

Interesting stuff!

Living in Washington State, I've always heard terms like Pineapple Express and never knew exactly how they impact weather patterns. Thanks for the clear explanation!

Living in Seattle I am

Living in Seattle I am certainly used to the Northwest Drizzle! I loved the historical context in the article, thank you for the educational content. Well Done!

As you see, I live in

As you see, I live in Solvang, CA. Every few years, we end up with this Pineapple Express - & this one was a doozy! No particular problems were I live. But people in the burn areas around Santa Barbara were definitely sweating it. Two of the three reservoirs on the Santa Ynez River are spilling and the third is almost there (less than 6 feet to go). The fun thing in southern and central California is that, as the leaves fall back east, the grass grows greener here if the rain falls as it should. It has already reached "gotta wear sunglasses green."

Very interesting, a great

Very interesting, a great explanation of why we had the December we did! I like the history of the name as well.

I was in Hawaii during the

I was in Hawaii during the holidays and experienced this storm. It rained for 5 days with flooded roads and mudslides! Now I know what it was all about! Thanks.

Very glad to have another

Very glad to have another weather blog. Not many can offer long range forecasting. Another site that offers long range forecasts using additional models than FA is Try it if you love weather.