Geoscience Reference
In-Depth Information
the warm and moist tropical Pacii c Ocean, near Hawaii; hence they have
been nicknamed “Pineapple Expresses.” Recent research describes these
storms as “atmospheric rivers,” and they ot en result in the worst l oods
in the West, particularly in California. When they follow on the heels of
arctic storms that leave several feet of new snow on the mountains and
freeze the soil (creating an impermeable surface), atmospheric rivers pack
a strong meteorological punch that can be especially deadly. h e warm
rains, unable to penetrate the surface, rapidly l ow over the surface, causing
extreme runof .
In 1861-62, however, immigrants did not recognize the climatic warning
signs. h ey had never experienced such extreme l ooding in the twelve years since
the Gold Rush began, though lesser l oods were not uncommon in the region.
h at year, though many of the western states experienced their worst
l oods on record, California bore the brunt of the damage. h e costs were
devastating: one quarter of the state's economy was destroyed, forcing the
state into bankruptcy. h e tragic 1861-62 l oods may have temporarily served
to awaken the residents of California and the West to the possible perils of
their region's climate. h ey saw nature at its most unpredictable and ter-
rifying, turning in a day or an hour from benign to utterly destructive. But
the costs to the state went beyond the loss of life, property, and resources;
California's spirit and coni dence were badly shaken.
h e message to residents of the lowlands was clear: living in the large val-
leys of the West is risky, even deadly. h ese valleys were created over time
by the rivers that continue to l ow through them, and the broad, l at valley
bottoms are called l oodplains for good reason: the rivers periodically spill
over their banks and spread across the broad expanses.
But this message has been lost in the hurley-burley growth during the
century and a half since, as California's population, agricultural production,
and technological innovation soar, transforming the state and its economy
beyond all expectation. Development in California and the West proceeds
with homes and towns built in exactly the same places that were obliterated
150 years ago. Residents now live in l oodplains throughout the American
West, despite the known risks to life and property. Perhaps modern western-
ers are not so dif erent from their forebears, many of whom were pioneers
or '49ers panning for gold. At er the great 1861-62 l oods, Brewer wrote of
Californians: “No people can stand calamity as this people. h ey are used
to it. Everyone is familiar with the history of fortunes quickly made and
as quickly lost. It seems here more than elsewhere the natural order of things.
