Hundreds of persons returning to their flood-wrecked homes in New Orleans after 1965's Hurricane Betsy.
Enlarge / Hundreds of persons returning to their flood-wrecked homes in New Orleans after 1965's Hurricane Betsy.

Looking back at the history of Atlantic hurricanes since the late 1800s, it might appear that they are on the increase.

After 2005, the year had the third-highest number of tropical storms in the Atlantic. Five of the six most destructive Atlantic hurricanes have taken place in the past ten years.

In the year of 2022, there are no major hurricanes until late in the year when Ian andFiona hit. There have been eight hurricanes and fourteen named storms in the Atlantic. Small sample sizes can be misleading when looking at trends in hurricanes. There is so much variability in hurricanes that we need to look further back in time to see the true trends.

Hurricane evidence goes back thousands of years.

Evidence shows that the Atlantic has experienced stormier periods in the past than we have seen recently. It is not good news. It shows that we may beunderestimating the threat hurricanes pose to Caribbean islands and the North American coast in the future.

The natural records hurricanes leave behind

Waves and currents can sweep sand and gravel into coastal ponds and lagoons when a storm is near.

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Fine sand and organic matter fall into these areas under normal conditions. A distinct layer is left behind when sand and gravel washes in.

You can see the different layers of the cake. It is possible for scientists to see the same effect by plunging a long tube into the bottom of the coastal marshes and ponds and pulling up a large amount of silt. Coarse sand can be seen when we look at the layers of sand in the soil.

Evidence of Atlantic Hurricane activity has been documented with the help of the sediment cores.

The red dots indicate large sand deposits going back about 1,060 years. The yellow dots are estimated dates from radiocarbon dating of small shells.
Enlarge / The red dots indicate large sand deposits going back about 1,060 years. The yellow dots are estimated dates from radiocarbon dating of small shells.

New England, the Florida Gulf Coast, and the Florida Keys are just a few of the locations where we can see decade to century-scale patterns in Hurricane Frequency.

It is nearly impossible to discern individual layers deposited within decades of one another because others are lower-resolution. They can be very useful in determining the timing of the most intense hurricanes.

The long-term picture for the Atlantic Basin is dependent upon the records from the Bahamas.