Unrelenting and unprecedented, back-to-back Atlantic hurricane seasons have punished the Gulf and East coasts of the United States. An unsurpassed 49 named storms have formed over the warming Atlantic waters since the start of the 2020 season, with a record-setting 18 striking the Lower 48 states, including seven hurricanes.

Scientists say this record-setting stretch of storminess is connected to a period of heightened hurricane activity that began in 2017 but may become increasingly common as the planet warms.

Few coastal communities from Texas to Maine have been untouched by the onslaught of cyclones, and the Gulf Coast has been hit particularly hard.

Louisiana has become a magnet for these storms, with four hurricanes and two tropical storms striking its coast since the start of the 2020 season. Some areas, such as Lake Charles and Grand Isle, have been hit more than once and have yet to recover.

Remarkably, two of the strongest hurricanes in Louisiana state history, Laura and Ida, have occurred in the past two years. The high-end Category 4 storms, each of which roared ashore with 150-mph winds, are only matched by the Last Island Hurricane of 1856. Along with their destructive winds, the duo pushed ashore a devastating storm surge, or rise in ocean water above normally dry land. Laura was blamed for 30 deaths in Louisiana, while Ida was responsible for about the same number of fatalities.

Before and after images show the devastation from Hurricane Ida

The wrath of many of these storms extended far inland because of their swaths of copious rainfall. Disastrous flooding unfolded from Ida’s remnants in the Northeast, causing more than 50 deaths.

The price tag of these storms is staggering and still mounting. Seven of last year’s landfalling tropical storms and hurricanes were deemed billion-dollar weather disasters by the National Oceanic and Atmospheric Administration, with total damage of over $42 billion.

While the costs of this year’s hurricane season are still being tallied, damage from Hurricane Ida on its own is sure to balloon into the tens of billions of dollars.

Meanwhile the 2021 hurricane season still has two months to go.

Why are so many storms striking land?

Decades of record-keeping show U.S. hurricane seasons have alternated between extremely busy and eerily quiet periods. The barrage of storms in the past two years is an extension of a very active period that began in 2017.

Before 2017, the nation recorded a 10-year landfall drought. It was the longest interval on record without a hurricane rated Category 3 or stronger making landfall in the United States. From 2009 to 2016, in a course of eight years, 13 named storms came ashore.

“We know the reasons for the hurricane drought,” said Suzana Camargo, a climate scientist at Lamont-Doherty Earth Observatory at Columbia University. “For instance, there were some patterns of winds that led to many hurricanes to avoid the continental U.S. for a few years. And now it seems that we are in the reverse pattern.”

The landfall drought ended when the Category 4 Hurricane Harvey slammed into Texas in 2017. Then came Category 4 storms Irma and Maria that same year, which hit the Florida Keys and Puerto Rico.

Since 2017, five storms rated Category 4 or stronger have hit the Gulf Coast in as many years, a record number over such a time interval.

Phil Klotzbach, a hurricane researcher at Colorado State University, linked the increase in landfalling storms to a persistent zone of high pressure off the U.S. East Coast over the past five hurricane seasons. The clockwise circulation around the high has frequently pushed storms in the western tropical Atlantic toward the Caribbean and Gulf of Mexico.