U.S. hurricane forecasters have added yet another storm to the record-shattering 2005 Atlantic hurricane season, taking the total to 28.
A routine post-season review of weather data revealed a previously undetected subtropical storm that occurred near Portugal’s Azores Islands in early October, the U.S. National Hurricane Center said in an update published this week.
A subtropical storm is a cyclone that has some of the same characteristics as a tropical storm and has maximum wind speeds of 39 mph or more. The new storm, which only lived a couple of days, was not given a name.
The 28 storms were the most since record-keeping began 150 years ago. The previous record was 21, set in 1933.
The hurricane center’s post-season reviews also revealed that Hurricane Emily, which hit Mexico, briefly reached Category 5 status.
That made Emily the only Category 5 hurricane on record to form in July and gave the 2005 season an unprecedented four Category 5 storms. The others were Katrina, Rita and Wilma.
Category 5 storms are the most powerful on the five-step Saffir-Simpson scale of hurricane intensity with sustained winds of more than 155 mph. They are rare in an average hurricane season, which sees only about 10 tropical storms and hurricanes.
The 2005 Atlantic season also produced a record 15 hurricanes. Katrina became the most expensive storm in U.S. history when it burst the levees protecting New Orleans in August. It killed about 1,300 people across the Gulf coast and caused at least $80 billion in damage.
Last week the World Meteorological Organization retired the names of hurricanes Dennis, Katrina, Rita, Wilma and Stan because of their level of destruction and death.
Weather experts say heightened hurricane activity could continue for another 20 to 30 years because of a natural swing in climatic conditions in the Atlantic. Some scientists fear that global warming could also be increasing the intensity of hurricanes.