A Category 5 hurricane is plowing headlong into Mexico and being reported as the strongest one on record. Some have already linked it to global warming. The hurricane, named Patricia, has sustained winds of 200 mph (lasting at least one minute) and a barometric pressure of 880 millibars (mbar). Patricia was first named a tropical depression on Oct. 20, and quickly developed into a Cat 5 hurricane over the warm Pacific Ocean. It is currently tracking North East and is expected to make landfall Friday around 11 a.m. near Manzanillo, Mexico.
As reported previously here, an extraordinarily strong, naturally occurring El Niño event—which is marked by warmer sea surface temperatures—is what many climatologists believe fuels powerful storms like Patricia. And all the moisture it picks up over the Pacific Ocean eventually gets dumped as heavy precipitation. In fact, up to 20 inches of rain is forecast for Mexico, which could cause landslides, flash flooding, and wreak havoc. As thousands of people are evacuated from Mexico’s Pacific coastal communities, the U.S. National Hurricane Center says that if Hurricane Patricia makes landfall as a Cat 5 storm, it could be “potentially catastrophic.”
Since recordkeeping only began in 1959 and tracks only those hurricanes that make landfall, no one can say definitively if Patricia is actually the strongest hurricane ever or simply the strongest ever recorded in the tropical Pacific using modern methods. That’s one reason news reports, including this article, are careful to include the words “on record” in their headlines or copy. The previous record holder was Hurricane Linda with peak sustained winds of 185 mph and a barometric pressure of 902 mbar.
Also, hurricanes and cyclones are normally separated out and listed by region, e.g., Eastern North Pacific, so it’s a bit misleading to use headlines that blare “Strongest Hurricane in Western Hemisphere.” In reality, the real headline is that Patricia is the strongest hurricane recorded in the Eastern North Pacific region since people started keeping records in 1959.
Previous storms, such as 1959’s Hurricane Patsy, have “incomplete pressure readings, since they were never estimated and only taken by ships, land-based observations, or recon aircraft when available.” Some of the previously recorded hurricanes only had their pressures measured when they were still Category 4 storms. The record holder for a hurricane forming the latest in a season is still the 1959 “Mexico” hurricane, which became a Cat 5 storm on October 27.
The most intense eastern Pacific hurricane was 2014’s Cat-4 Odile, “with a pressure of 918 millibars, lower than that of some Cat 5 hurricanes, such as Emilia (July 1994).” For example, Patricia’s current pressure is 880 millibars. Before the start of “reliable geostationary satellite coverage in 1966,” the number of “eastern Pacific tropical cyclones was significantly underestimated.”
Before 1959, hurricanes did form in the Western Hemisphere. But because the storms never reached land and remained at sea, they were never recognized. It should be noted, there were “no Cat 5s during the late 1970s, 1980s, and early 1990s.” Because of the strong El Niño currently in place in the tropical Pacific, the likelihood of a Hurricane forming is much more favorable because of “warmer sea surface temperatures and reduced wind shear.”
This is one of the reasons Cat 5s cluster in single seasons. Historically, though, this doesn’t mean a hurricane can’t form outside of an El Niño event. During the season of 1959, there was “neither an El Niño or a La Niña, but had two Category 5’s (Patsy and the ‘Mexico’ Hurricane) and was the deadliest Pacific hurricane season ever recorded in history.”
Hurricane Patricia is expected to weaken once it reaches the “mountainous terrain of Mexico,” continuing to “produce heavy rain in central parts of the country and into Texas over the weekend.” Mexican officials have declared a state of emergency for dozens of coastal towns, and are preparing for the worst.
But, as is often the case, some news outlets are already trying to tie Patricia to global warming, even though there is no factual proof that climate change had anything to do with this or any other hurricane. The most likely cause, as expressed by meteorologists, is the strong El Niño event occurring along the tropical Pacific Ocean. Warmer water and reduced wind shear fuels hurricanes. A very simple formula for a very dangerous storm.