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Tragedy leads to better icing alerts

A new forecast model with the ability to produce computer maps can better predict icing conditions

On the night of Jan. 26, 2007, the stern trawler Lady of Grace capsized and sank in brutal cold on Nantucket Sound, with the loss of all four crewmembers.

The icing aboard this Coast Guard harbor tug's pilothouse shows how the vessel could become top-heavy.

A winter storm was threatening and, after three days on Georges Bank, the 79-foot fishing boat was headed back to New Bedford, Mass., with 15,000 pounds of fish on board.

The water on Nantucket Sound was 37 degrees. Most of the day and into the night, the air temperature was 7 to 12 degrees. The trawler was taking a 20-knot northwest wind and 4- to 7-foot seas on the starboard bow, and this was kicking up a lot of spray as the steel-hulled vessel hustled home.

The likely reason Lady of Grace sank was an accretion of ice so thick on its deck, bulwarks, rigging and pilothouse top that the 30-year-old fishing boat became top-heavy, rolled and failed to right, according to a Coast Guard investigative report. The crew’s survival suits remained stowed in their bags — three in a pilothouse locker and a fourth in the master’s stateroom.

Neither the EPIRB nor life raft deployed automatically, as they should have. Investigators believe they were embedded in the thick ice that had built up at a rate of 3/4 of an inch an hour as the spray froze to the vessel.

When raised from the bottom, Lady of Grace yielded the bodies of two of its crew: Antonio Barroqueiro, 50, the captain, in the pilothouse; and Mario Farinhas, 62, the cook and a deckhand, in his stateroom. The other two crewmembers — Joao Silva, 50, a deckhand; and Rogerio Vendura, 54, the engineer — remain missing two years later and are presumed to have been breaking ice on deck when Lady of Grace capsized.

“Freezing spray will stick on a boat like glue,” says Gaetano Brancaleone, 67, now retired after 42 years as a fisherman out of Gloucester, Mass. Brancaleone says there are a couple ways to beat icing. First, make sure the boat is stable to start out with. If it’s not, icing obviously will only make it more unstable. Second, when ice starts to build up, go at it with big wooden mallets the size of a sledgehammer. Brancaleone, the former skipper and owner of the 75-foot stern trawler Paul & Dominic, used to carry six or seven mallets on his boat. He would stop the boat so no one would slip and fall off, and all hands would go on deck to hammer away.

“If you didn’t do that, it would reach a point where the boat would lean to one side,” says the former president of the Gloucester Fishermen’s Association. “Ice always accumulates on one side [to windward]. That creates an unstable boat.”

Another way to avoid severe icing is to stay abreast of the weather and heavy-icing forecasts, and adjust your plans accordingly. “Any information you can get is useful,” Barroqueiro says. That’s what set three oceanographers to thinking about applying the Northeast Coastal Ocean Forecast System, a combination of sophisticated ocean and weather forecast models, to provide three-day icing forecasts for the Gulf of Maine and Georges Bank.

The scientists are Changshen Chen and Brian Rothschild, of the University of Massachusetts at Dartmouth, and Robert Beardsley, of Woods Hole Oceanographic Institution. They used this integrated model to analyze weather and ocean conditions the day Lady of Grace sank to help them understand when icing occurs and to see if they could adapt their model to use wind, current, wave height, and air and water temperature forecasts to make icing forecasts.

The model they developed “hind-cast” that conditions the night of Jan. 26, 2007, would have caused moderate to heavy icing on Lady of Grace as she made her way home. That is consistent with Coast Guard findings in interviews with the crew of another fishing boat that was out that night and was attempting to get home before the storm.

Crewmembers from the Debbie Sue, a 74-foot fishing vessel home-ported in Point Judith, R.I., reported 10 inches of solid ice on the handrails on the upper deck, 6 inches on top of the pilothouse, 4 to 6 inches on the starboard side of the hull, 10 to 14 inches of ice hanging from the wire stays, and 10 to 12 inches hanging from the outriggers.

“[The new forecast model] has the real potential to save lives,” says Beardsley.

NOAA already produces icing forecasts, but the beauty of the new model is its ability to produce computer maps with “higher spatial resolution,” Beardsley says.

Chen has found a way to dice up the waters in a flexible grid that can project icing conditions to a resolution as fine as 1/3 to 1 kilometer in coastal regions and 100 meters in Nantucket Sound. Beardsley says if Lady of Grace’s skipper had had access to a computerized map of icing conditions with that kind of detail, he might have changed course, hugged the shore, or stopped in the lee of Nantucket Island, where icing conditions were less severe.

“The icing potential was very high in the middle of Nantucket Sound, where the boat went down,” he says.

Though limited for now to the Northeast, the icing forecast model could be used anywhere in the country, which is divided into 12 “regional ocean observing systems” that collect ocean and weather data and plug it into forecast models, Beardsley says. He and his colleagues won’t do any forecasts themselves but will give their data to the National Weather Service.

“We’re starting to look at it,” says Joe DelliCarpini, the NWS’s science and operations officer in Taunton, Mass. “We think it will be a better [forecasting] tool and more accurate tool. It allows us to be more geographic-specific.”

Using ocean and weather data gathered from buoys and satellites, the combined ocean-weather model predicts icing as well as air and surface-water temperatures, surface winds, air pressure, salinity, rain and water currents for up to three days. “The system is updated daily through integrating the data into the model, which ensures the reality and reliability of the forecast,” Chen says.

The model’s forecasting prowess also can be used predict flooding, algae blooms, and salinity, oxygen content and other water-quality characteristics. It can help the Coast Guard in search-and-rescue by predicting currents and water temperatures — information that’s vital for predicting the onset of hypothermia when survivors are in the water and tracking the drift of disabled boats and life rafts. Fisheries managers can use the model to foresee salinity and water temperature, and monitor the health of nursery waters. Health officials can use the information to track red tides, monitor beach waters, and decide on beach closures.

“There are a lot of different applications,” Beardsley says. The most dramatic for now is the icing forecasts.

Chen hopes they will prevent losses like the Lady of Grace.

This article originally appeared in the April 2009 issue.