During the Civil War, many meteorologists on land stopped keeping records.
But officers on U.S. Navy ships offshore — including those blockading Charleston — didn't.
Now, a private-public effort plans to mine that data, putting online millions of weather observations from Navy log books for the years 1861 to 1879. The format will make it easier for researchers and the general public to comb them for storm and climate patterns.
The multi-ship Navy blockade off Charleston, which was in place throughout war years, is a particularly valuable trove for the work, said Kevin Wood, the lead research scientist.
"We can say more about extreme weather events, how frequent they have been in the region," said Wood, who works at the National Oceanic and Atmospheric Administration's cooperative institute at the University of Washington in Seattle.
The data overall could help researchers forecast trends more accurately. Previously recorded weather reports have been used for a variety of historic studies by emergency managers for disaster planning and by regulators reworking building codes, among other projects.
"The Civil War is generally this huge missing era of weather overall, and ship logs the (largely) forgotten piece," said Cary Mock, a University of South Carolina climatologist who has studied the logs for hurricane information.
"The expedition hurricane was a very unusual early November storm that ran up the coast from Louisiana to New England," he noted, referring to a hurricane that wracked the Navy expedition force attempting to land in Port Royal in 1861. Records of that time are spotty.
Muster rolls for enlisted men and officer lists will be digitized as part of the work, providing one more resource for genealogy researchers. The data will be stored and accessible in the national catalog at the National Archives.
The work furthers previous efforts that including loading into a federal database hundreds of millions of weather readings from ship logs, stations and other sources around the world from as far back as the 1820s. That became part of a warehouse of weather data at the National Centers for Environmental Information in Asheville, N.C.
The Civil War was marked by extreme weather, such as one of the worst droughts in history and the devastating November 1861 hurricane.
The data, assembled by Wood and a team of citizen science, university and NOAA researchers, would be a valuable complement to the work that's already been done, Mock said.
The work is being paid for by a $482,018 grant from the nonprofit Council on Library and Information Resources. It's expected to take four years, Wood said.
The first records should be posted at the archives within a few months.