By LILLY LOUGHNER
It was a cloudy summer day on the Morehead City Waterfront when the crew of Atlantis IV heard a booming sound not more than 50 feet from their vessel.
The crew had docked at the Olympus Dive Center to refill its scuba air tanks when a waterspout appeared. The sea-spun funnel had formed quickly in the adjacent channel and began to chum on the surface.
“You could see the tail coming out of the cloud, and it stopped traffic on the bridge — those people had a really good view,” Renate Eichinger, first mate on the Atlantis IV recalls. “I could see the swirl on the water, and I kept my eyes on it. Luckily it wasn’t coming straight at us, but still, it’s not somewhere you want to be.”
The spout spun across the docks and onto the roof of the building that was once Ottis’ Fish Market. Overland, the spout-tumed-tornado grabbed loose shingles and tossed them through the air, before whirling off into the distance and dissipating.
“It didn’t seem enormous, but it was strong enough to throw things around,” says Eichinger, who had helped undock the boat and back it out of the spout’s damaging path.
Atlantis Charters runs 90 to 100 diving and fishing trips annually, and the crew spots waterspouts on roughly five of those trips. While Eichinger has no qualms about going out to sea everyday, and even enjoys watching the spouts dance beneath the distant cloud line, she’s no storm chaser.
‘You don’t want to mess around with them. They’re beautiful, but from a distance,” Eichinger warns.
Boaters, who are most likely to spot waterspouts, may not think to report their sightings to forecasters: “It’s just part of the day, like getting in a traffic jam on the way to work — we’ll hit rough waters and not think much about it,” says Eichinger.
But tales of these “traffic jams” are just what Tim Armstrong, forecaster with the National Weather Service (NWS) office in Wilmington and local waterspout expert, wants to hear. Stories like Eichinger’s, if reported, can improve the accuracy of waterspout risk forecasts, a new service provided by the NWS in Wilmington.
The Wilmington forecast office oversees five coastal counties, from Surf City in North Carolina to the South Santee River in South Carolina, and monitors marine weather up to 40 miles seaward.
“We’re trying to forecast fair weather waterspouts, usually the kind we see overwater off the Carolinas,” says Armstrong.
A second type of waterspout, or tornado over water, is less common. Spawned by massive thunderstorms, “tornadic-type” waterspouts are more easily detected by radar, with warnings broadcast in advance.
The waterspout risk forecasts first became operational last summer as part of the Surf Zone Forecast. Accessible on the Web, the forecast provides information about coastal hazards, such as lightning and rip currents, as well as daily weather and surf conditions.
Wilmington’s online SurfZone Forecast is enhanced by graphics that display various hazards, including a color-coded map detailing waterspout risk levels — none, low, moderate and high. Mariners and beachgoers can check the waterspout risk forecast, which is issued twice daily during spring and summer months, the peak times for waterspouts.
“Last year was ourfirst run with the waterspout forecast. We’ll look things over and see how we can make it better,” says Tom Matheson, warning coordination meteorologist with the NWS in Wilmington. “It’s a good estimate, at this point, based on science.”
The forecast is modeled after a five-year effort in the Florida Keys. The world’s capital for waterspouts, the Keys experience up to 500 waterspouts each year due to warm sea surfaces surrounding the heated islands.
Although waterspouts along North Carolina are not as frequent as in the Keys, they are dangerous and sometimes even tornadic, according tojoseph Golden, senior meteorologist and waterspout expert with the National Oceanic and Atmospheric Administration (NOAA).
“The primary warm axis of the Gulf Stream and large coastal bays and inland waterways are favored regions of waterspout occurrence,” Golden explains in the Encyclopedia of Atmospheric Sciences chapter dedicated to waterspouts.
Currently offered nowhere else along the North Carolina coast, the waterspout forecast draws interest from other NWS offices. In Morehead City, Thomas Kreihn, NWS meteorologist-in-charge, is following the Wilmington prototype to see how it functions this year.
As waterspouts form and fade in the Atlantic — each a slender, spinning column anchored only by limits of cloud and sea — they are difficult, if not impossible, to predict.
Less-established weather systems rarely show up on radar. “Weaker, smaller waterspouts are pretty much undetectable,” says Jeff Orrock, warning coordination meteorologist with the NWS in Raleigh, who formerly worked with the Morehead City office. Therefore, forecasters often must rely on boaters’ reports to spread warnings.
Waterspouts are visible, often from miles away, and last for only minutes. “Most of the time you see them before a warning comes out,” says George Purifoy, owner of Olympus Dive Center.
Purifoy has seen up to five or six in clusters on diving or fishing trips and has learned to “just steer away from” threatening spouts. “Usually we’re the ones that call in the warning,” he explains.
The NWS in Wilmington issues a special waterspout forecast over NOAA Weather Radio on high-risk days. For maximum safety, all vessels should be equipped with VHP marine band radios that receive warnings from frequencies within the weather band or rebroadcasts of warnings from the U.S. Coast Guard.
Open communication is a boater’s best protection against fair weather waterspouts, according to Jim Bahen, former North Carolina Sea Grant fisheries specialist who now works as a recreational fishing guide.
“We’re all the time, constantly, talking on the radio. Everyone’s always looking out forthe other person — that’s what you have to do out there,” he says of boaters.
Although they generally can’t identify waterspouts as they occur, the forecasts do help people better plan a day on the coast, and safeguard life and property when risks are high. But, according to Armstrong, the forecast can’t work to its full potential without input from those it serves.
“Basically we make a forecast everyday, and we never hear whether or not a waterspout occurred unless someone reports one,” Armstrong explains. “[The reports] help us grade and verify our forecast and help improve the service we provide our public.”
The NWS receives reports of 6 to 10 waterspouts on average per year through the Wilmington office. However, “if you look at the entire North Carolina coastline, I’m sure that there are a couple dozen waterspouts forming a year,” says Armstrong.
DISSECTING THE SPOUT
“On the still summer mornings, when there’s nothing going on, when its perfectly peaceful right around sunrise, you may see a waterspout out there spinning — kind of Oz-like,” Matheson describes the more benign fair-weather beauties.
For Matheson, these waterspouts seem “almost miraculous.” They usually don’t come ashore, but rather, sit over the water for a few minutes, stabilizing the early morning atmosphere as the land breeze carries the nighttime drift of cooler air out to the ocean.
When the cooler air of the land breeze front undercuts the warmer air over the warm summer ocean, the atmosphere becomes unstable because the discontinuity in temperature creates a horizontal spin. These waterspouts become less of a destructive force than an “efficient vertical mixing process,” Matheson explains.
“The spinning process is a more efficient way to transfer mass, to transfer the warm air upward,” he adds.
Tall, puffy cumulus clouds with flat, dark bottoms are formed by updrafts and are signs that air is rising and could spin up a waterspout on the water surface. As the air rises beneath the cloud and above the surface-fed vortex, a connection between sea and sky is made, and a waterspout is formed.
“The updraft grabs the spin and stretches it out. It’s kind of like skaters pulling their arms in, which causes them to spin faster and faster,” Orrock explains.
Sunrise to noon is the most conducive time for waterspout formation — before the afternoon sea breeze creates enough wind shear to break up fair weather waterspouts. Wind shear is the tendency for winds to change direction and speed between slightly different altitudes.
According to Orrock, fair weather systems are fragile, and require low wind shear to form and remain stable.
Once formed, waterspouts are an impressive sight, as their winds can reach 100 mph and travel at a speed of about 10 knots. The lifespan of a waterspout varies but usually lasts no more than 20 minutes. “The bigger, the more impressive it bob, the longer it will last,” Orrock says.
PROMOTING OCEAN SAFETY
When atmospheric conditions are right, forecasters can predict the risk of waterspouts on any given day. But you don’t have to be a trained meteorologist to take safety precautions.
Safety Tips for Boaters
* Be informed: Know the time of day that waterspouts form, the typical cloud structures and associated weather patterns.
* Be prepared: Check forecasts for storms and threatening weather and always give a float plan to your local marina before leaving safe harbor.
* Be aware of your surrounding: Pay attention to weather inland to avoid surprise thunderstorms. Listen to weather radio alerts and warnings issued for storms brewing inland as well at sea.
* Steer clear: If you do cross paths with a waterspout, remain calm. Remember the typical waterspout affects a very small area. “Observe its motion or direction and move away from it in a straight line as fast as you can,” Armstrong advises.
* Seek safe harbor: “If you’re dealing with a true thunderstorm that is becoming a tornado, that’s a whole different story,” says Orrock. A large, tornadic thunderstorm could produce lightning and many different waterspouts.
Coastal communities and visiting beachgoers also should watch the forecasts for waterspout risks. “It’s not uncommon for them to skirt onto the beach,” Orrock says.
While onshore, waterspouts can do the same damage associated with small tornados. However, since waterspouts thrive best over the smooth, frictionless ocean surface, they don’t survive long on land. The sand, dunes, trees and buildings found along most beaches usually rip a waterspout’s circulation apart within a few seconds.
Boaters may worry about imploding windows or torn canopies. But according to Purifoy, waterspouts also could be armed with slippery projectiles — raining schools of fish.
“The waterspout could be a mile away, and you’ll actually see fish landing and things hitting the water — it’s rare, but it does happen.”
Forecasters Need Your Help!
Visit the National Weather Service (NWS) in Wilmington online. The new waterspout risk forecasts can be viewed at www.erh.noaa.gov/ilm/beach.
To report a waterspout, immediately call the NWS office, 910/762-4289, with details on the time and location of the sighting.
Information and pictures also can be sent to Tim Armstrong at Timothy.Armstrong@noaa.gov.
This article was published in the Spring 2005 issue of Coastwatch.
For contact information and reprint requests, visit ncseagrant.ncsu.edu/coastwatch/contact/.