Weather measurements made in the past are like pieces of a big puzzle. When put together by a supercomputer, they
show how the earth's climate is evolving.

From long-term changes, like warming global temperatures and rising seas, to the increased intensity of weather systems, like hurricanes, blizzards, droughts, and floods.

These measurements can also show how weather has influenced history.

One of those storms, which could have changed the outcome of the American Civil War, was the Expedition Hurricane.

In October 1861, a large fleet of Navy ships, The Great Naval Expedition, sailed from Hampton Roads. Their mission? To seize a key harbor in the South. But when they arrived at their secret destination, Port Royal, South Carolina, they were hit by a severe storm. Once the seas calmed, the fleet successfully took Port Royal for the Union. But because of the severe weather, it was a close call.

Records from these historic events help today's scientists build better climate models, giving us more confidence in future projections and in the actions needed to address them.

Visit www.archivesfoundation.org/digitalweather to learn more.