The Pineapple Express
January 29, 1998
By Mark Hoover
It's beginning to look like the predictions that the worst is yet to come for
El Niño effects this year might be correct. The next couple of storms
that are brewing up right now, out in the Pacific, look like textbook El
Niño cyclones, and the meteorologists are salivating. I'm ready and
waiting for the word from the storm fliers as these storms spin up and head for
This week, we are seeing the first signs of what meteorologists call a "regime
change," or a shift in the patterns of the polar jetstream. It's this
jetstream that conducts storms from the Pacific onto the west coast—the
so-called stormtrack. The storm that surprised scientists yesterday
demonstrates the change this stormtrack is undergoing. This morning, central
and northern California are getting drenched, while the mountains inland are
receiving several feet of snow.
Last fall, scientists based their predictions of triple normal rainfall in
California this winter on an expectation that a fork would develop in the polar
jetstream—a classic El Niño pattern. The southern branch of this
fork would then carry storms to California, rather than farther north.
However, so far Oregon and Washington have already received roughly triple the
normal January rain and snow this winter, because the jetstream hadn't forked
yet, and all the storms stayed to the north.
If the first signs of this southerly shift pan out, we'll see the so-called
"Pineapple Express" fire up, and begin to dump on California what it's already
been dumping on the northwest states. Like clockwork, every few days, warm,
moist air between Hawaii and Alaska will react with cold polar air, form
storms, and then be conducted by the south branch of the jetstream to
Meanwhile, on the other side of the equator, Peru has been slammed and dunked
by a furious series of El Niño-induced rainstorms for the past 72 hours.
Early reports suggest that over 70 people have lost their lives, and 22,000
more are homeless, in the worst flooding of at least 50 years. The coastal
regions of Ica in southern Peru, and Tumba and Piura in northern Peru, have
been devastated by relentless rains and surging rivers, which have overrun
their banks and gouged into the surrounding country.
These coastal Peruvian regions are exactly where we will be filming the NOVA
television show in a few weeks' time, and that only makes the disaster seem
more immediate, and frankly, more frightening.
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