Why Hurricane Humberto Became Storm Amy

Tropical weather followers may have been confused last week when Hurricane Humberto suddenly became Storm Amy. Why do European windstorms take on different names, and what is the criteria used in this naming system?  Here is a look back at Storm Amy's destruction, as well as a few things to know to help avoid the confusion in names.

Storm Amy Roars Across Northern Europe

What was once Hurricane Humberto became Storm Amy last week before roaring across northern Europe on Friday and Saturday, killing one man and leaving over 200,000 people without power. According to the BBC, a man in his 40s was killed in Letterkenny, Ireland. The majority of the power outages happened in Ireland, with customers in Scotland and England also reporting being in the dark.

Not surprisingly, the record-breaking storm also led to widespread train and airline delays throughout the United Kingdom (U.K.) and beyond. Dublin Airport confirmed 115 flight cancellations as winds peaked at speeds near 50 mph. A top wind gust of 96 mph was reported in the community of Tiree in western Scotland. A gust of 92 mph was confirmed in Magilligan, setting a new record for the most powerful wind gust in October in Northern Ireland.

Storm Amy also set a new record for the lowest pressure notched at a land station in the U.K. during the month of October. The air pressure came in at a mere 947.9 mb.

Although Amy delivered significant impacts across the U.K., it was a shell of what it once was when it roamed the Atlantic as Hurricane Humberto, a storm that peaked as a monster Category 5 event.

Understanding the European Naming System

Why did Hurricane Humberto suddenly take on the name of Storm Amy? While the National Hurricane Center (NHC) is responsible for naming storms that form in the Atlantic and the Eastern Pacific closer to the U.S., other nations do not always recognize these names.

The meteorology agencies of the U.K., Ireland, and the Netherlands work together to come up with their own naming systems for storms that impact this corner of the world. The new season for European windstorms begins on September 1. This is because the North Atlantic storm track picks up in intensity and frequency during the fall and winter months.  As such, it makes sense that Amy is the first storm of this new season.

The agencies of these countries pick each year's list of names from suggestions submitted by the public.  Each year's list also reflects popular names that represent the diversity of the three regions.

Just like the NHC assigns names to storms in an attempt to raise public awareness of the dangers, the European weather agencies also give potentially dangerous weather events an official name. The last storm of the 2024 - 2025 season in this part of the planet was called Storm Floris. This August event had a significant impact on the region, necessitating the use of a name to urge residents to prepare. Reserach has shown that naming a storm can save lives as it raises awareness.

Similar to how the NHC uses wind speed criteria to define and name tropical weather events, the U.K. Met Office issues a name when it declares an amber warning, a level 2 of 3 on the alert system. Amber warnings are issued when the Met Office forecasts widespread impacts from a storm. A level 3 of 3 red warning is issued when a storm presents a threat to life.

Most storms in this part of Europe are designated by wind speeds. However, the Met Office can also issue an amber warning for just rain or snow impacts. This differs from the NHC, an agency that focuses on tropical weather events

One caveat to this complicated naming system in different parts of the Atlantic is how the Met Office uses the presence of a closed center of circulation to determine if the name will change. For example, had Humberto arrived near the coastline of Europe with its center of circulation still closed, the Met Office would have retained the name Humberto, calling it "Storm Humberto." However, because Humberto had already transitioned to a post-tropical event when it merged with a cold front pushing across the North Atlantic, it took on the name of Storm Amy.

The next name up on the U.K. Storm Center list is Bram.