Geographer recreating Atlanticís early hurricane history
By Peggy Binette, email@example.com, 803-777-5400
While meteorologists are busy forecasting and tracking this year’s crop of hurricanes using the latest satellite technology, University of South Carolina geographer Dr. Cary Mock is combing through 300-year-old British ship logs for weather data to detail hurricanes of the past.
Mock, an associate professor of geography in the university’s College of Arts and Sciences, is the only academic researcher conducting historical maritime climate research. He has amassed approximately $700,000 in grants from the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA) to research and reconstruct the hurricane and severe weather history of the Atlantic Coast.
“Maritime climate work is a new movement in the field,” Mock said. “There’s a great deal of detail to early ship’s logs. They provide a lot of data on extreme weather events. We know every South Carolina hurricane back to 1722 because of the British ship logs.”
Working from plantation records, diaries, newspapers and other early 18th- and 19th-century written accounts, Mock has spent the last decade building a comprehensive historical database of hurricane activity that extends back hundreds of years before modern weather instrumentation.
In 2007, he turned his attention more fully to ship logs, both U.S. and British, knowing that the maritime records would provide greater detail. This summer, he spent several weeks in England, his sixth trip to research log books from the British Royal Navy, East India Company and whaling logs. He’ll return to England in late fall.
“Ship log books provide more detail than land records,” says Mock. “The log records are kept hour by hour for wind scale, wind direction and barometric pressure. They’re very descriptive.”
Mock says he has reviewed nearly 3,000 ship logs from England and the U.S. National Archives and Records Administration and various New England maritime archives, dating from the early 1700s to the 1870s. Of those, he said 300 – 400 have provided useful information. Few whaling logs -- about 28 -- provided any hurricane information.
What makes maritime records so useful is that standard methods for record keeping were used, improving as ship technologies improved, he says.
When reviewing a ship log, Mock says he first looks at wind scale, which is measured from 0 – 12. Six or above indicated a tropical storm or a “gale,” the term commonly used until the advent of “hurricane” in the late 19th century. Winds in the 10 – 12 range hint of something exciting, a possible hurricane, Mock says.
Mock then looks at the barometric pressure, wind direction and weather descriptors for more clues. Of the 12 basic weather descriptors used, the most common include Q for squalls, C for cloudy, R for rain, L for lightning, U for ugly, G for gloomy and B for blue sky.
U.S. ships adapted the British system of meticulous record keeping. While British logs go back to the early 1700s, U.S. logs only extend back to the early 1800s. The earliest useful U.S. log book for hurricane data is from the War of 1812, says Mock.
Vivid notes were commonly written in the margins of the logs by the weather columns. An excellent example of this is a log kept by the U.S.S. Para that detailed a hurricane near South Carolina on Sept. 16, 1863. Etched in the margins was a description of heavy rains in the 4 p.m. hour that developed to “heavy squalls from the Eastward increased to a gale” by 5 p.m. Entries at 5:10 and 5:20 p.m. described the dragging of anchors, the laboring of the vessel, the battening of the hatches and the securing of everything on board.
Mock says U.S. ship logs were particularly thorough during the Civil War because of the Union naval blockade. In contrast, the Confederate Navy has few records.
“I discovered about 50 percent of the hurricanes in the ship logs,” he says. “I made changes to the strength of hurricanes that we knew about based on what I found in the logs. Many of the ones in New England were Nor’easters. I also discovered a new hurricane in 1714 and a hint of another one hitting Georgetown in 1729. Unfortunately, many Georgetown records were destroyed during the Civil War, which would provide more information.”
Mock’s database shows 11 major hurricanes affecting South Carolina: 1713, 1728, 1752, 1804, 1813, 1822, 1893 (2), 1954, 1959 and 1989.
One discovery of particular interest to Mock was one from a U.S. log about a hurricane that hit Oct. 31 – Nov. 1, 1861.
“The U.S. fleet was headed to Beaufort to take over,” he says. “The storm went from the Gulf across Florida, up the Carolinas to New England. It is the only storm that I know of to do that.”
He also has about 150 logbook records detailing the weather conditions that led in part to the sinking of the Hunley submarine.
While the 19th century offers compelling hurricane accounts, it is the early ship logs that hold the most value for Mock.
“The oldest written accounts show fewer storms because there was limited information,” he says. “Changing just one to three hurricanes a year using ship-log data makes a difference.” We average nine to 10 hurricanes in the Atlantic basin each year. A change of three storms can swing a hurricane season from low to high easily. That is important when you are looking at trends over the span of hundreds of years.”
What trend can climate experts deduce from Mock’s now more complete database?
“The level of hurricane activity is just as active today as it was in parts of the 17th and 18th centuries, even though there was different weather, such as wind shear, during the period of the little ice age (1500 – 1850),” he says.
Encouraged by the wealth of weather information in maritime records, Mock has begun to look at England’s East India Company and British Royal Navy ship logs to determine the typhoon history of Hong Kong. He says there has been very little work done to reconstruct the typhoon and severe weather history in the Western Pacific and almost nothing done before World War II.
“The National Hurricane Center and NOAA are very interested in the promise of maritime climate research,” he says.
That’s good news because, Mock says, in addition to U.S. and British records, there could be untapped weather treasures in early ship logs from Dutch, French, Spanish, German and Russia vessels.