5 Natural Disasters Headed for the United States
By Jim Gorman
Earth is one rough place. Even the most devastating
storms of recent years pale in sheer destructive
power against outsize natural disasters of the
past, such as continent-smothering ice sheets,
ocean-raising floods, super volcanoes and the
occasional asteroid. Because cataclysms will always
be a regular feature of life on Earth, PM consulted
with leading scientists to detail five more disasters
that may be in store. Some will be beyond human
control; others could be disasters of our own
making. Either way, prepare for a real doozy.
40-Mile-Long Mudslide, Washington State
On an overcast afternoon high on Mount Rainier,
a rocky slope slumps and then cuts loose from
the mountain. Small rock slides are common on
the volcano's steep flanks, but this one is different.
Most of Mount Rainier's west face is in motion.
Into the tumbling maelstrom go millions of tons
of ice from the Puyallup and Tahoma glaciers.
House-size rocks disintegrate in the downward
crush. “With Rainier's active hydrothermal
system saturating the rock, the landslide would
reach the base of the slope as a flowing mass
of watery, muddy debris,” says Kevin Scott,
scientist emeritus at the U.S. Geological Survey's
Cascade Volcano Observatory (CVO).
So a lahar is born--a volcanic mudflow--and a
nightmare realized for the approximately 150,000
Washington residents who live and work on the
solidified debris of past flows. The mass of roiling
mud, rock and trees, traveling at 60 mph, would
quickly funnel into the canyons of the Puyallup
and Carbon rivers, where it would rise 180 ft.
high before spreading into the lowlands as a 15-ft.
wave. The 5000 residents of Orting, at the rivers'
confluence, would have less than 45 minutes to
evacuate. People downstream, in towns such as
Puyallup and Sumner, might have twice that long.
Despite its iconic standing, 14,410-ft. Mount
Rainier is pocked with corroded, unstable rock
capped by a cubic mile of ice and snow. The mountain--weakened
from the inside out by acids resulting from upwelling
magma--has partially collapsed many times in the
last 5600 years, unleashing mudflows that have
inundated five of six major drainages. Six of
those lahars surged at least 45 miles to reach
The USGS gives a 1-in-7 chance of a similar event
occurring in anyone's lifetime. And, says Dan
Dzurisin, a CVO geologist: “There's no guarantee
there would be any advance warning.”
80-Ft.-High Tsunami, Atlantic Coast
A massive collapse of Cumbre Vieja in the
Canary Islands would cause a tsunami to radiate
all the way across the Atlantic Ocean to the East
Coast. PHOTOGRAPH BY J. SCHWAKE/ALAMY
Cumbre Vieja, the most active volcano in the
Canary Islands, lurches as a violent earthquake
wracks its upper slopes. A third of the mountain
breaks away and plunges into the Atlantic Ocean,
pushing up a dome of water nearly 3000 ft. high.
They don't yet know it, but tens of millions of
Americans from Key West, Fla., to South Lubec,
Maine, have just 9 hours to escape with their
The collapse of Cumbre Vieja unleashes a train
of enormous waves traveling at jetliner speed.
The first slam into nearby islands, then the African
mainland. By the time they reach the East Coast
of North America, the waves are up to 80 ft. high,
and in low-lying areas, sweep several miles inland.
When tsunamis strike the United States, it is
usually Hawaii or Alaska that take the hit. But
topography and population density put the East
Coast in a special risk category. “More
Easterners are exposed to potential tsunamis--from
the Canary Islands or the Cape Verde Islands--than
the people on the West Coast, which has a steep
coastline and few lowlands,” says Steven
Ward, a geophysicist at the University of California,
Santa Cruz. A Cumbre Vieja eruption in 1949 opened
a mile-long, 20-ft.-deep fissure near the crest,
forcing the volcano's western face to slump several
feet. A 1971 eruption didn't budge it.
Marine geologists at Southampton Oceanography
Center in Great Britain have a different take.
They conclude the volcano would collapse in stages--
at worst threatening nearby islands. Ward calculates
only a 5 percent chance Cumbre Vieja will trigger
a tsunami in a given century, but that when it
does a chunk of earth 15 miles long, 9 miles wide
and nearly 1 mile thick will plunge into the sea--a
landslide 250 times larger than the collapse of
Mount St. Helens.
The tsunami's probable trajectory within 5
hours of the collapse of Cumbre Vieja.
The tsunami's potential range of destruction
9 hours after the collapse of Cumbre Vieja
Magnitude 6.9 Earthquake, Mississippi
The New Madrid Seismic Zone, which extends into
five states, is part of a rift that formed more
than 500 million years ago when tectonic forces
began pulling the continent apart.
Ten miles beneath Caruthersville,
Mo., stress along an ancient rift zone releases
in a violent spasm. Shock waves from the magnitude
6.9 earthquake roll 160 miles up the Mississippi
River Valley to St. Louis, and 75 miles downriver
to Memphis, Tenn. The soils under Memphis ripple
like a shook rug. Century-old brick buildings
heave, then crumble. Sewer and water lines rupture.
Gaslines snap. Downtown, the 14-story federal
building, a decade overdue for quakeproofing,
rains 3-ton panels.
all eyes are fixed on California as the site of
the next “Big One,” damage from a
quake along the New Madrid Fault--which runs for
150 miles between Marked Tree, Ark., and Cairo,
Ill.--may be greater. The hot, shattered crust
beneath California absorbs seismic energy quickly
and focuses it at an epicenter, says Gary Patterson,
a geologist at the University of Memphis. But,
he says, “the relatively hard, cold slab
of rock beneath the central U.S. allows that energy
to travel great distances.” A quake's impact
zone is at least 10 times larger on the New Madrid
Fault than on the San Andreas, and its shock waves
The New Madrid Fault has produced the strongest
earthquakes in the contiguous states: three tremors
near magnitude 8.0 that struck from December 1811
to February 1812. Odds of a quake of that scale
are small: 7 to 10 percent in the next 50 years.
But factor in unprepared citizens and infrastructure
and even a 6.0 earthquake, which has a 25 to 40
percent chance of occurring, would be a disaster.
“There's a lot about the New Madrid we
don't know,” Patterson says. “But
what we do know is very concerning.”
195-MPH Hurricane, Florida
Packing maximum sustained winds of 195 mph, Hurricane
Lyle slams into Coral Gables just south of Miami.
The breadth and intensity of the storm dazzles
meteorologists, who rank it the strongest hurricane
ever to hit the U.S. mainland.
On the north side of the storm's eye, Miami Beach,
which has the second highest housing density in
the country, is in shambles. Many residents don't
evacuate, believing they are safe in concrete
high-rises. They are wrong. Then it is too late,
as the causeways connecting them to the mainland
wash out. Waves riding a 15-ft. storm surge gut
oceanfront condos up to the third story; windows
blow out, allowing wind and rain to ravage upper
floors. The storm surge sweeps over the island,
carrying wreckage into downtown Miami, where the
70-story Four Seasons Hotel and Tower is reduced
to a sodden shell.
Low-lying coastal areas would be hit twice by
a supercharged storm—as waves rushed in
and then back out. PHOTORAPH BY WARREN FAIDLEY/CORBIS
Block after block of homes in Coral Gables, West
Miami and Sweetwater--many not yet retrofitted
to the tough codes imposed after Hurricane Andrew
in 1992--are blasted down to roofless frames.
Waist-deep floodwater inundates areas as far north
as Fort Lauderdale. Insured losses exceed $100
billion--nearly twice the amount caused by Katrina--making
Lyle the costliest natural disaster in U.S. history.
Katrina should have been a wakeup call, but coastal
development has continued unabated, exposing the
4 million people in Florida's Miami-Dade and Broward
counties to deadly monster storms. Warm water
is rocket fuel for hurricanes, and global warming
is predicted to heat tropical oceans by 4 F in
the next century. Sea surface temperatures in
the tropics have already risen by about 1 F since
Researchers at Georgia Tech and at the National
Center for Atmospheric Research in Boulder, Colo.,
have measured a near doubling in the annual number
of Category 4 and 5 storms during the past 35
years. And Kerry Emanuel, professor of meteorology
at MIT, has found that Atlantic storms today wield
twice the destructive force as those in 1970.
Wind speeds increase with altitude, and so a Category
4 storm at ground level can be a full category
higher at the top of a building. While the storm
surge scours the first two stories, overpressure
blows out windows in the highest floors, exposing
the interiors to wind and rain.
Some scientists dispute the global warming-hurricane
connection. They attribute the intensity of recent
hurricanes to natural cycles, or they contest
the accuracy of early data and the objectivity
of techniques used to analyze it.
Supercharged or not, hurricanes promise to wreak
unprecedented damage in the decades ahead for
one simple reason: More people have put themselves
in harm's way. Coastal zones from Texas to North
Carolina have gained 24 million residents since
Climate-Changing Ocean Disruption, North
Winters in the Northeast begin to bite with a
ferocity last seen during the deep freezes of
1936 and 1978, when icebreakers plied the Mississippi
and Hudson rivers. Winter temperatures in Washington,
D.C., begin to approximate those of Boston. Extreme
drought grips the Midwest, sending grain commodity
prices soaring; crops fail and farmers spin into
bankruptcy. Climate patterns go haywire. London,
Paris and the Scandinavian capitals shiver through
their coldest winters since 1850. Summer monsoons
in India and China weaken, affecting harvests
that feed hundreds of millions of people. Fisheries
decline when plankton populations collapse. Drought
and flood push worldwide agricultural losses to
The cause of the big chill is an unlikely culprit:
global warming. The northeastern States, eastern
Canada and, primarily, Europe enjoy warmer climates
than they otherwise would because of an ocean-based
system of heat delivery called thermohaline circulation.
This vast ocean conveyor sweeps warm, salty water
from tropical latitudes north along the surface.
After shedding heat to the atmosphere, the chilled
brine becomes denser and sinks. Thousands of feet
beneath the surface it flows back toward the equator,
completing the loop.
Freshwater melt from the Greenland ice sheet contributes
to a layer of buoyant water that is beginning
to cap the North Atlantic Ocean. PHOTOGRAPH BY
But as the climate warms disproportionately at
the poles, the gears of the system begin to wobble.
Freshwater runoff from Greenland's ice cap and
from melting glaciers across the Arctic, combined
with increased precipitation, could form a thick,
buoyant cap over the North Atlantic. Already,
the great gyre may be sputtering. The surface
of the North Atlantic is becoming noticeably less
salty, and thus less driven to sink.
Thermohaline circulation shut down as recently
as 8200 years ago, and some scientists contend
that the Little Ice Age of 1300 to 1850 was due
to a hiccup in the system. The chance of another
collapse is hotly debated. Terrence Joyce, a senior
scientist at Woods Hole Oceanographic Institution,
calls it “unlikely” if Greenland's
ice cap continues to melt at the current pace.
However, “Greenland is a wild card,”
he says--its melt rate remains unpredictable.
Michael Schlesinger, an atmospheric scientist
at the University of Illinois, Urbana-Champaign,
calculates a 45 percent chance of the system shutting
down in the next century if nothing is done to
slow global warming.
Cold, dense water typically sinks near the Arctic
and flows in deep currents to the equator. When
this cycle is disrupted, warm water is not pushed
as far north along the surface.
Ice core samples indicate the switch from temperate
to bitter could be measured in mere years--and
last for centuries. The timing of such an event
will determine the severity of its consequences.
“If the shutdown happens 100 years from
now, it will bring us back to where we are now,
canceling 4 to 6 F of atmospheric warming [predicted]
in the Northeast,” Joyce says. “If
it happened tomorrow, that would be something