The 2021 hurricane season hasn't been a quiet one, featuring its share of record-breaking storms, like Hurricane Ida – the second most intense and damaging storm to ever make landfall in Louisiana, behind Katrina in 2005.
That storm brought with it sustained winds of 240 km/hr and a damaging storm surge that flooded communities.
There were many more hurricanes and tropical storms from Ana to Victor, leaving only the name Wanda left on the main hurricane name list, with only weeks to go before the season's 'official' end on November 30.
However, it's significantly quieted down over the last several weeks. Below, I explore why and why we should not let our guard down just yet.
IS OCTOBER NORMALLY THIS QUIET?
The answer is no. As you can see in the tweet below, from Colorado State University hurricane forecaster Phil Klotzbach, the fact that we have not had a major hurricane or typhoon – defined as a storm of Category 3 strength or higher – anywhere on Earth since September 25 is extremely rare.
This has only happened twice in recorded history.
While we tend to not see the typical long-track developing storms off the west coast of Africa this late in the season, we do get "in-close" developers.
Meteorologists refer to these types of storms as "home-brews" or "home-grown" tropical systems.
In terms of impact, it really doesn't matter where a hurricane is born, only whether it makes landfall. Plenty of October hurricanes have done just that.
In 2018, hurricane Michael made landfall in Mexico Beach, Florida, on October 10 as a Category 5 hurricane, with sustained winds of 257 km/h. Storm surge was estimated at almost 3 metres (20 feet). The damage certainly reflected the impact of the surge, and in fact, storm surge is the number one killer when it comes to hurricanes in the United States.
FAVOURED DEVELOPMENT ZONES IN OCTOBER
Though tropical systems don't pay much attention to the calendar, they can develop in various regions over warm water at any time of year. Scientists who've examined the data found there are certain zones that are more prone to seeing October tropical systems.
This time of year, the storms tend to develop closer to the coast, and sometimes can be triggered off the tail end of a cold front in the southern U.S. If they happen to stay long enough over warm waters of the Gulf of Mexico, then there is no reason why we couldn't get another major hurricane landfall before the season is done.
OCTOBER CAN SOMETIMES PROMOTE HYBRID STORMS
A storm name that will never be forgotten: superstorm Sandy.
Sandy was the tenth hurricane of the 2012 season, second major hurricane of that year, and a Category 3 storm at its peak when it made landfall in Cuba. It then moved up the U.S. eastern seaboard and its windfield expanded significantly. It became the largest Atlantic hurricane on record as measured by diameter, with tropical storm-force winds stretching to 1,850 kilometres.
Sandy was infamously known for it's crucial left hook into the New Jersey coast. This storm was what meteorologists refer to as post-tropical, as it had lost its true tropical characteristics and started to interact with colder air masses, though it didn't lose any of its overall impact or severity.
This hybrid-like storm would do over $70 billion in damage in total.