Your body and the earth's surface have a lot in common. Both are mostly water, and the blood in your body is actually not that different from sea water (in composition). Our sun is like the earth's heart; energy from the sun pumps water from the tropics to the poles in a vast network of currents. However, occasional "hiccups" in the water world spawn hurricanes, floods and tsunamis that disrupt the normal flow of the system, often with disastrous results.

Imagine that you're a drop of water in the vast, tropical Sargasso Sea in the Atlantic Ocean. It's the end of August 1992, warm and salty, but not at all calm. A 100-mph wind is whipping the waves into a seething cauldron. They'll call this Hurricane Andrew back in Miami, and you're a part of it, feeding it enough energy to make 40,000-foot-high clouds spiral into walls around a low-pressure "eye." You are a speck of froth on the water, and are swept across the Gulf Stream as you add warm moisture to the hurricane's fury. Driven by 145-mph winds, you slam into south Florida as part of a 17-foot-high storm surge, destroying hundreds of homes and huge tracts of ecologically important mangroves. You now have the dubious honor of being part of the costliest storm in American history. Had you come ashore only 20 miles north and hit Miami squarely, you would probably have been part of the deadliest one too.

A 250-mph tornado drops out of the sky and sucks you off the face of the earth, spraying you 15,000 feet into the clouds. It's so cold that you freeze into ice and plummet thousands of feet until strong updrafts within the thunderstorm below waft you up another 35,000 feet. Along the way you pick up static charges that attract ice crystals. You grow into a pea-sized hail stone. And, after several more wild rollercoaster rides through the clouds, you become the size of a golf ball. With the added weight of the ice, you break loose from the convecting drafts and hurtle down to the earth in central Florida, the lightning capital of the western hemisphere.

A 50,000oF bolt of lightning, five times hotter than the surface of the sun, connects with the ground from 35,000-feet and discharges 100,000 amperes of electricity from the cloud. The stroke superheats the air and creates a shockwave that is heard as thunder for miles around. It ignites the years of accumulated forest debris and starts a brush fire. Ice doesn't stick around long in central Florida in the summertime, so you melt and mix into the falling rain, dousing the fire. Florida was lucky you were around to help put that fire out because wildfires consume hundreds of square miles of brushland, forests, and homes every year.

Now you are swept up in surging stream water that carries you to a lake already filled to the brim from the torrential rains. The lake doesn't normally receive so much water, so the river draining it floods its banks and forces you to leisurely flow through several homes built on the floodplain. Your meandering destroys the homes - and the lives of their owners.

Next, you are sucked into a swirling sewer and pushed through an outfall back into the sea. An along-shore current swashes you up and down the coast with the tides. You pick up some sand along the way, and erode pockets in the beaches - one grain at a time.

An offshore breeze jets you out into the Gulf Stream current, which carries you up to the cold North Atlantic. After weeks of evaporation, you have become saltier and denser and sink into the dark, cold depths to start your journey back to the equator along the sea-bottom. You thought it would be dark and desolate here, but you can see a shower of tiny bioluminescent animals putting on an exquisite light-show. On the bottom, you drift through beautiful gardens of white and red tube worms standing three feet tall that surround 20-foot-high pipes of dark, sparkling minerals. The pipes spew out scalding water heated by the earth.

You continue your slow drift southward over a submerged mountain range that runs down the middle of the Atlantic Ocean You are hot from lava spewing from undersea volcanoes that may someday become new islands like Iceland, Hawaii and Montserrat. Without warning, the water shudders from a series of undersea earthquakes that help relieve the stresses caused by magma rising into the earth's crust. Sometimes these quakes occur under land where the earth's great plates collide and shake the ground hard enough to destroy buildings and bridges.

Suddenly the volcano over which you drift erupts into a boiling cauldron of seawater. You are caught in a mammoth bubble that carries you 8,000 feet up to the surface of the ocean. Superheated steam from the bursting bubble wafts you another 15,000 feet up into the troposphere where you are immediately swept eastward by the 200-mph winds of the jet stream.

A week later and half a world away, you precipitate in a blizzard of snow over Mt. Redoubt in Alaska. The heat from this awakening volcano melts the ice and snow under you, and the whole white veneer starts sliding down the side of the mountain. Within minutes you're caught in a blinding white wall of powder moving at 100 mph, ripping up trees by their roots, knocking down chalets, and covering everything in your path. Finally, the avalanche deposits you in a warm valley, where you melt and flow through a braided stream back into the Pacific Ocean. You've arrived here about 500 years sooner than if you had completed your journey through the deep waters of the world's oceans.

But "Pacific Ocean" is a misnomer; it is not always pacific and peaceful. Besides the huge typhoons that seasonally stir its waters into a tempest, the surrounding "Ring of Fire" is the most seismically active region in the world; it is the birthplace of more volcanoes, earthquakes, and tsunamis than anywhere else on earth.

Floating placidly now in Blying Sound along the western shore of the Gulf of Alaska, you hear a growing roar in the distance that sounds like a bursting dam. A huge wave traveling up the inlet sucks the water out of the bay and pulls you out in the strongest current you've ever felt. Fish are left flapping helplessly on the dry seafloor as you rush past. You are lifted towards the sky by an improbably high wave, a tsunami 40 feet tall and growing as it approaches the shore at more than 60 mph. It starts to curl over the town of Seward, and then crashes down on the streets and buildings 60 feet below. You smash through the town driven by the great weight of water behind you, battering everything in your path. In a few short minutes that seem to last forever, you toss and tumble over the landscape, and turn the town into a trash heap. As you surge inland over the highways, buildings and neighborhoods, the water around you fills up with big chunks of trees, homes, and entire vehicles.

The energy packed into this great wave (and the ones to follow) is unbelievable. It rips up or knocks down everything in its path. When the valley in which the town lies finally fills to its brim, the water recedes slowly at first, then in a gathering rush. Everything that was ripped up by the incoming surge is now carried out to sea by the ebbing maelstrom, like children's beach toys washed away in the surf.

This tsunami, spawned 10 hours ago by an earthquake 5000 miles away, moved through the water at 500 miles an hour. It started out only a couple feet high in a deep open ocean trench, and moved unnoticed past ships. But as it scraped the ocean floor closer to shore, the energy-packed water piled up on itself the way car wrecks do on a foggy interstate. Fortunately, an alert issued by the Pacific Tsunami Warning System helped most people to reach high ground in time to save themselves, even though the tsunami turned their world upside down less than five hours later.

Ultimately you are sucked back into the cold waters of the Gulf of Alaska, and you meander into a great gyre of water circulating slowly across hundreds of miles of the North Pacific Ocean. Overhead, a low-pressure trough off the Canadian coast churns up the wind and sea to produce a thick, dank haze of microscopic water droplets draped over the ocean; air and water become indistinguishable, and the horizon indiscernible. You're one of the lucky droplets that evaporates and gets carried southeastward by the gathering storm to warmer climes. As you approach the rugged coast of the western United States, you rise with the wind to scale the high mountains. You cool down, condense, and fall onto the slopes of the Cascades as rain.

You filter down through the normally arid soils until you reach rock, and you flow ever downward along its sloped surface. The dirt above the rock slowly absorbs you and turns into slippery mud. This overburden starts to slide down the hill with the added weight and lubrication. Gaining speed, it grows into a catastrophic landslide that sweeps houses off their foundations and dumps them into the valley below.

The (only?) good thing about landslides is that they deliver new topsoil to the valley floor, creating an environment where life can bloom. You are content now in your new surroundings and with your new role - encouraging new plant life to poke through the fresh topsoil. It's satisfying to finally be productive after having wreaked so much destruction in your journey around the world.

Epilogue

As a drop of water, you accept that your environment is continuously changing. Nothing remains constant. Occasionally you flow over land, which also moves albeit at a much slower pace. While most of the earth's inhabitants don't build their nests and dens in dangerous areas, humans do. They seem to have little sense of danger, building their fragile structures on barrier islands, unstable land, and even flood plains! They've got to know that they're living on borrowed time. Maybe they think they'll get away with it, but sooner or later you know they will learn to live with the earth's spasms. Otherwise these natural events will continue to be natural disasters for them. And this is just a drop in the ocean when you consider the greatest hazard of all: a direct hit by a heavenly body such as a comet or large asteroid (less than a 1/2 mile wide), that would decimate the biosphere by causing several years of nuclear winter. A 110-mile-wide impact crater near the Yucatan Peninsula is considered to be evidence that just such an event caused the extinction of the dinosaurs 65 million years ago. Will it happen again?