Off Africa's Coast, a Hurricane Nursery

A churning storm, viewed from the international space station.

A churning tropical storm, viewed from the international space station. NASA hide caption

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Bob Pasken, of St. Louis University, launches a dropsonde from the DC-8 plane.

Bob Pasken, of St. Louis University, launches a dropsonde from the DC-8 plane. The dropsondes are cylinders about the size of a model rocket and jammed with electronics to record data on atmospheric pressure, temperature, humidity and wind. NASA hide caption

itoggle caption NASA
Michael Douglas (right) and Gerry Heymsfield

Michael Douglas (right), a scientist from the National Oceanic and Atmospheric Administration, and Gerry Heymsfield of NASA Goddard Space Flight Center, on board an airplane specially designed to hunt out and measure baby hurricanes. Jon Hamilton, NPR hide caption

itoggle caption Jon Hamilton, NPR

When a hurricane reaches land, it meets a violent end.

In 2003, Hurricane Isabel slammed into the coast of North Carolina. The storm's death throes caused billions of dollars in damage.

That was the end of the storm's life. The beginning took place several weeks earlier and thousands of miles away, on the other side of the Atlantic.

Hurricane Isabel was born near the Cape Verde islands off the western coast of Africa. The same waters produced Andrew in 1992 and Frances in 2004.

Storms from this area — branded Cape Verde hurricanes — tend to form in the summer and fall.

During the 2006 hurricane season, a group of scientists spent a month in Cape Verde to learn more about the birth of these storms. I spent several days with the team during its mission.

ISO Stormy Weather

Cape Verde is a republic of 10 small islands known for surf, sun and a melancholy music that blends the sounds of Portugal and Africa.

Most tourists come to the island of Sal for a quick tan. That makes it easy to spot the hurricane scientists at the hotel bar. They're the pasty ones talking about lidar data and mesoscale convective systems.

They don't spend much time on the beach. You're more likely to find them flying over it in a DC-8 airliner that serves as a sort of laboratory with wings.

Today I'm flying on the DC-8 with the NASA team. Many of them have already been working for more than three weeks. They have only a few days left to find a weather pattern that will become a hurricane.

Piecing Together the Puzzle

Robbie Hood of NASA's Marshall Space Flight Center in Huntsville, Ala., says the goal is to figure out why certain storms evolve into hurricanes.

"It's kind of like a jigsaw puzzle," Hood says. "There are certain pieces that we're putting together. And we've got part of the picture of how a hurricane is developed. But we don't have the complete picture yet."

Cape Verde hurricanes begin as atmospheric disturbances called "easterly waves" that appear over Africa. Some waves eventually become hurricanes as the tradewinds carry them across the Atlantic. Others just disappear. It's not clear why.

Gerry Heymsfield of NASA Goddard Space Flight Center in Maryland says the wave we're following on my flight with the team is typical.

"This here is just a very big group of thunderstorms," he says, pointing to a satellite image on his laptop that shows the storm we're following. "It's maybe 100, 200 miles across."

The scientists and technicians on board will spend the next seven hours flying in and around those thunderstorms. They'll measure wind shear, convection, rotation, lightning, rainfall, humidity, even the dust particles swirling about. All of these things may help decide whether a storm grows into a hurricane.

Once the plane reaches altitude, NASA team-members unbuckle their seatbelts and spring into action.

"Hey Mike, Mike come here," Hood says to Michael Douglas, a scientist from the National Oceanic and Atmospheric Administration. Together they study a chart of the plane's planned flight.

"You know on these legs we're starting to get into the convection more and there's a little bit of lightning right there," Hood says. They decide to change the flight plan slightly.

This DC-8, which is operated by the University of North Dakota, was designed to carry 150 passengers. But many rows of seats have been replaced by racks of equipment. They hold lasers, radars, radiometers, particle collectors and dozens of computers.

A walk down the aisle lets you visit a dozen meteorology labs in about as many steps. The air is filled with jargon.

Parachuting into a Hurricane

Near the back of the plane, a bearded man swivels between a computer screen and what looks like a small torpedo tube jutting up through the floor. He's Bob Pasken from St. Louis University.

Pasken is launching dropsondes. They're cylinders about the size of a model rocket, but jammed with electronics. As they fall, they send back data on atmospheric pressure, temperature, humidity and wind.

Pasken says there's one question on everyone's mind right now: Will this storm turn into a hurricane?

"Nobody's ever seen the genesis before," says Pasken, "Or at least studied it in detail as much as we are."

Today, the storm system is rotating counterclockwise the way a hurricane does. But it's weak and disorganized. It's probably not a baby hurricane.

So the mood is subdued when the plane finally touches down after dark. The team has just two flights left. And they still haven't found what they came for.

The pilot, Bill Brockett, holds a post-flight briefing. He talks about some of the obstacles the crew encountered during the flight. Brocket says it's not easy to chase a storm system through airspace controlled by several different countries.

Then he wraps up. "That's all I have. I'll see you all in the living room," he says, a reference to the bar in the hotel lobby.

There's just time to make it back to the hotel for dinner. After that, there's a stage show featuring Cape Verdean dancers and a Michael Jackson impersonator.

But by then, the scientists have wandered off to grab a few hours sleep.

By noon the next day, the NASA team is airborne again.

There's tension on this flight. The entire mission was put together on a tight budget. Now it's running short on flight time and supplies. And still no baby hurricane.

Bob Pasken has started rationing dropsondes.

"We've got 33 sondes left," he explains. "And we have three flights. This one and two others. So rather than try and use them all up on one storm we're trying something new today."

Instead of dropping a sonde, the pilot drops the entire airplane from 30,000 feet to 500 feet. There's turbulence. Coffee spills. Scientists lurch around the cabin. Backpacks and briefcases have to be tied down.

About four hours into the flight, Robbie Hood decides this storm system just isn't worth it. She calls for an early return.

"This will probably be the last day that we work this storm," she says. "The forecast is showing something bigger coming off the coast in a few days. And that will probably be our last case of this mission."

Back on the ground, Hood explains why missions like this one are important. For one thing, she says, they're a way to improve hurricane forecasting in the United States.

But the biggest payoff may be in countries that are less prepared for powerful storms. Hood says people in the states tend to think of 2005 only in terms of Hurricane Katrina.

"But also there was Hurricane Stan last year that flared up on the eastern side of the Yucatan," she says. "It flared up very quickly and moved inland to Guatemala, and 800 to 1,000 people were covered up with mudslides because of the heavy rain.

Hood says if scientists can learn to spot Cape Verde hurricanes sooner, that could give people in places like Guatemala more time to prepare.

On their last flight, Hood and the rest of the team finally got what they came for. They followed a baby storm system that went on to become a hurricane named Helene.


