Out of Names, National Hurricane Center Calls New Storms by Greek Letters

This season is the second time ever that the list of 21 storm names has been exhausted

Tropical Storm Beta reached the coast of Texas on Monday night. NOAA/NESDIS/STAR GOES-East

Last Friday, Tropical Storm Wilfred formed in the eastern Atlantic Ocean. Each year the World Meteorological Organization (WMO) sets a total of 21 alphabetical names for each hurricane season, with each name used only once every six years. Storms are never named using the uncommon letters Q, U, X, Y and Z, so Wilfred is the last planned storm name for the 2020 hurricane season. But the peak of hurricane season has only just passed, and two new tropical storms have already formed.

The pair of new storms now go by the Greek letters Alpha and Beta. The first formed briefly by Portugal, and the second made landfall in Texas on Monday night. New storms will be named using Greek letters for the rest of hurricane season, which lasts through November. This season is only the second time that all alphabetic names have been used up—the last time was in 2005.

As Oliver Whang reports for National Geographic, there isn’t any fanfare at the National Hurricane Center headquarters when a storm’s name is assigned. When a storm’s average wind speed passes 45 miles per hour for a day, it’s designated a tropical storm and gets a name. Above 75 miles per hour, the storm is a hurricane.

A name is “just the natural next step,” says deputy director of the NHC Edward Rappaport to National Geographic. “There’s no shouting from the rooftops.”

The last time the Atlantic saw a storm named Alpha was October 22, 2005, which makes this hurricane season about a month ahead, Matthew Cappucci reports for the Washington Post. This year's Tropical Storm Alpha was a relatively small storm, just 50 miles wide with maximum windspeeds at about 50 miles per hour.

Tropical Storm Beta made landfall in Texas on Monday night, Doyle Rice reports for USA Today. Louisiana and 29 counties in Texas declared disasters to manage the aftermath of the storm. Beta became the ninth named storm to make landfall on the continental United States this year, matching a record set in 1916, Chris Dolce writes for Weather.com.

By Tuesday afternoon, the NHC downgraded Beta to a tropical depression, but it still poses flood risks, Bill Chappell reports for NPR.

Wilfred, Alpha and Beta all formed on September 18—the last time three storms formed on the same day was in August of 1893, per Weather. This September has had ten named storms so far, another record-breaking month. The most recent busiest Septembers—in 2002, 2007 and 2010—had only eight named storms.

The current system for naming Atlantic storms was established in 1979. The WMO established six lists of 21 names, so that each list is repeated on the seventh year. The names alternate between traditionally men’s and women’s names. When a storm is particularly damaging, it is stricken from the list and replaced with a new name, as happened with 89 storms, including 1985’s Gloria, 2005’s Katrina, and 2017’s Harvey, Irma and Maria.

The WMO doesn’t allow replacement names to come from staff members, family members or friends. “It’s just taken from a generic list of names of a particular letter,” Rappaport tells National Geographic.

When the 22nd storm formed in 2005, the WMO chose the 24 letters of the Greek alphabet as the next storm names. That year, NHC named six storms for Greek letters, ending with Zeta on December 30.

NOAA predicted an active hurricane season in May, Alex Fox reported for Smithsonian magazine at the time. In August, NOAA predicted between 19 and 25 total named storms for the season. Contributing factors include a La Niña climate event that cools the Pacific Ocean and warms the Atlantic, fueling storms, as well as climate change.

Hurricane and tropical storm names have been useful both for keeping records of the season, and for raising public awareness.

“Giving it a name does call a greater attention to the system than it would have had otherwise,” Rappaport tells National Geographic. This is the fifth year in a row with an unusually active hurricane season, and perhaps the use of Greek letters as storm names will bring attention to the fact that something’s amiss.

Get the latest stories in your inbox every weekday.