Hurricane Patricia—the strongest tropical cyclone ever recorded—made landfall on Mexico’s west coast last Friday as a powerful category five, the first scale-topper to strike North America in eight years. The storm managed to pack winds of 200 MPH before making landfall, which is about as strong as a tropical cyclone can get—as far as we know, anyway.
The storm, which claimed at least six lives and all but destroyed several small towns in the path of its eye, was the first category five to make landfall in North America since Hurricane Felix struck Nicaragua in September 2007.
A category five storm making landfall anywhere in the world is one of the worst natural disasters possible, so the better outcomes in a situation like this are just lesser degrees of awful.
Even though Patricia lost a bit of its strength as it raced toward shore, it still smacked into Mexico with winds of 165 MPH, making it the most intense eastern Pacific hurricane to make landfall, and one of the strongest storms to hit the continent since reliable records began.
Despite its ferocious winds, the storm exacted a much smaller toll than feared due to the storm’s small wind field and the sparsely-populated land it hit. The extent of category five (157+ MPH) winds only stretched about seven miles on either side of the eye, and the entire hurricane force (74+ MPH) wind field was only about 60 miles across.
The storm made landfall on one of the least-populated parts of the country’s coast, laying waste to several small towns, but moving in just the right way that the worst conditions missed the cities of Puerto Vallarta (population ~200,000) and Manzanillo (population ~100,000).
While that was a less awful outcome than some of the other scenarios that were possible, the storm still hit several villages, killing several people and destroying hundreds of homes and businesses. The international media quickly lost interest in this storm once it was obvious that the forecast track would verify and the catastrophic winds would miss the big cities.
The worst media report outside of the partisan sewagesphere came from the Associated Press by way of AL.com, which went so far as to use a Cavuto mark in a Saturday morning article to imply that meteorologists oversold a category five hurricane making landfall because it only leveled small towns and not big cities, which weren’t forecast to see a direct hit in the first place.
An interview with a Michigan family in Puerto Vallarta serves as the centerpiece for the report.
The Sokols, a family of five from suburban Detroit, were supposed to fly out of Puerto Vallarta on Friday but ended up for hours in a shelter at a university after their flight was canceled. By night they were back where they began: at their hotel, and no worse for wear.
“It’s amazing it went from the worst in history to just some heavy rain,” Susanna Sokol said, noting that at least the hurricane gave her daughter a birthday to remember.
“It was pretty stressful for a while,” Tom Sokol said. “I felt guilty for taking my kids here.”
Whew! The American tourists are okay! Now, how about the Mexican residents who aren’t in the resort with the tourists?
There were early reports of some flooding and landslides, but no word of fatalities or major damage as the storm moved over inland mountains overnight. Television news reports from the coast showed toppled trees and lampposts, and inundated streets. Milenio TV carried footage of cars and buses being swept by floodwaters in the state of Jalisco.
No word! So, to recap, the tourists are fine and we hadn’t yet heard from the areas leveled by 165 MPH winds, so that warranted reporting that the storm was “overblown” and fell short of the “catastrophic” label applied to it by everyone with a shred of common sense.
This ugly coverage/headline combo from the Associated Press is a stark example of the media’s bias in covering weather disasters.
The fact that anyone felt okay publishing a story discounting accurate, dire warnings as “overblown” because the Americans in a tourist city were okay and only small towns were affected highlights the growing city vs. rural bias in weather reporting. The lack of regard for those affected is compounded by the fact that the event happened outside of the United States, which is, of course, the center of the universe outside of which there is no important news.
For 18 hours on Friday (October 23), Hurricane Patricia peaked with maximum sustained winds of 200 MPH and a minimum central pressure of 879 millibars. That’s insane. That’s record-breaking. It’s the most intense tropical cyclone we’ve ever recorded in terms of sustained winds, and the fourth-strongest we’ve ever recorded based on minimum air pressure.
200 MPH winds pretty much speak for themselves. These aren’t estimated values, either. Hurricane Hunters measured these winds on more than one occasion using dropsondes and advanced sensors on the aircraft as they flew through the thing several times on Friday.
That pressure reading of 879 millibars is also significant. If that doesn’t sound like much, standard atmospheric pressure at sea level is 1013 millibars. Most formidable hurricanes we see in the Atlantic bottom-out with pressures in the low- to mid-900s. Hurricane Katrina’s lowest surface pressure was 902 millibars. The lowest surface pressure ever recorded in a storm was Typhoon Tip’s 870 millibars back in October 1979.
How did Hurricane Patricia achieve such a feat? Very quickly, for one.
Patricia went from a 65 MPH tropical storm at 10:00 PM on Wednesday to a 160 MPH category five hurricane by 10:00 PM on Thursday. The storm had a minimum central pressure of 980 millibars at 4:00 AM on Thursday morning, and 24 hours later on Friday morning, that pressure had bombed to 880 millibars; this 100-millibar strengthening is the fastest pressure drop we’ve ever recorded in a tropical cyclone.
A hurricane looks like a hurricane due to rising and sinking air throughout the storm. The thunderstorms that make up the eyewall suck up air from the lower levels into the upper atmosphere, leaving less air (thereby lower air pressure) at the surface. Air rushes down from the upper atmosphere toward the ground to fill the void, and this sinking air warms and dries as it descends. This is how a clear, striking eye forms.
As the thunderstorms in the eyewall gain strength, their updrafts grow stronger, displacing more air from the surface and causing more air to sink to fill the void. Under ideal conditions—warm water, no wind shear, moist atmosphere—this process can evacuate enormous amounts of air and allow for a very deep center of low pressure to form. This process can occur very quickly in an event known as rapid intensification, and that’s what we saw last week.
Patricia encountered the ideal conditions to catapult it into the record books. For that 24-hour window right before landfall, it encountered very warm waters, precious little wind shear, and ample moisture, and it used it as efficiently as a storm could. The water off the coast of western Mexico was warmer than 30°C/86°F, which is more than sufficient to sustain a monster like this.
Storms that rapidly intensify over the water are fun to watch, but when they’re this close to land, it’s downright scary.
Grading the Forecast
Meteorologists have gotten pretty good at predicting the track of most tropical cyclones, but there’s still a lot of work to be done in predicting their future wind speeds. A storm like this is rare and obviously on the extreme end of the scale—computer models predicted that Patricia would strengthen, but neither they (nor anybody else, really) knew that Patricia would get as strong as it did pretty much until it started happening.
Safe to say we still have a long way to go to get better model intensity forecasts (Team Humans did better) pic.twitter.com/OnOwtjMXkV— Eric Fisher (@ericfisher) October 24, 2015
The above graph shows various solutions from weather models on Wednesday morning showing what they thought then-Tropical Storm Patricia would do over the next two days. They were in pretty good agreement that it would steadily strengthen before landfall. That black line shows Patricia’s actual strengthening trend.
Thankfully, we knew it would be a violent hurricane early enough that many residents in the storm’s path had at least two day’s notice that a hurricane was on its way. (Though, someone who went to bed on Wednesday night and slept late on Thursday woke up to a much more dire situation than they’d anticipated.)
The National Hurricane Center’s track forecast for Patricia was remarkably consistent. The center line just barely nudged westward, remaining within a few dozen miles of the actual landfall point between the time the storm formed on Tuesday and the time it made landfall on Friday. The actual point of landfall was solidly within the cone of uncertainty beginning with the first advisory.
There is no doubt in my mind that, despite the difficulty they had in predicting its intensity, the National Hurricane Center’s stellar track forecast and early watches and warnings saved lives. A storm this strong can kill hundreds of people even when it hits sparsely-populated areas. The fact that the reported death toll is below ten as of the writing of this post is astounding for a landfalling category five hurricane.
(Hey, mobile users: the above .gif is 8.34 megabytes, so be mindful if you choose to load it.)
Even the mightiest storm must come to an end. The storm began a swift weakening trend just before it made landfall as the eye started to fill with clouds, the eyewall started to deteriorate, and the storm encountered wind shear. Intense storms usually undergo eyewall replacement cycles, which is where one eyewall collapses as a new one forms to take its place. Microwave satellite imagery (above) shows that the storm’s eyewall started to deform just as it approached land, likely the result of interaction with land, increasing wind shear, and the beginning of an eyewall replacement cycle.
One of the strangest narratives that took hold during this ordeal is that the storm was hyped because it rapidly began to weaken once it made landfall.
That’s how hurricanes work!
Hurricanes derive their energy from warm ocean waters. Losing this bath water is like pulling the plug. This is why you hardly ever see hurricanes over cold water. This is why—except for one time in recorded history—hurricanes don’t make it to California.
A hurricane moving over land is like a human holding their head under the water. They survive for a little while, but they’ll die pretty quickly. It doesn’t help that rugged and mountainous terrain will kill a tropical cyclone at breakneck speed. The jagged land disrupts the winds and forces it to ingest dry air, killing the low pressure center at the surface and rapidly breaking apart the thunderstorms around its core.
One of the biggest examples of terrestrial destruction from this hurricane season was Tropical Storm Erika, the storm that threatened Florida for a few days this August. The storm shredded apart once it hit the mountains of Hispaniola, floofing away into nothing.
Another classic example is...well, Patricia!
It’s worth pointing out that “the strongest storm ever” has to be followed by “recorded,” or else it’s not exactly true. Even more accurately, Hurricane Patricia is the strongest storm ever recorded by wind speed. Some geeks will argue that it’s not really the strongest because it’s pressure that matters, not winds, but I don’t buy that because it’s the wind that shreds your house apart and sends shards of glass soaring through your skull, not the air pressure.
Hurricane Patricia is the strongest storm we’ve ever recorded in terms of winds. Despite what your local school board thinks, the Earth is 4.5 billion years old. Reliable wind speed records only go back into the mid-1900s, and even then, many of the early satellite reports were unreliable.
It’s impossible to truly know how strong a hurricane’s winds are unless you fly right in there and measure them or the eye passes over a well-built anemometer at sea or on land. It’s very likely that Super Typhoon Haiyan’s winds were stronger than satellite estimates of 195 MPH, for example, and there are countless more storms that have formed during the course of history that were at least as strong (if not stronger) than Hurricane Patricia, and we have no way of knowing it.
Hurricane Patricia likely wasn’t the strongest storm ever. We haven’t been smart enough for long enough to know that for sure.
Another (insignificant) debate that played out during and after the storm was whether or not “category five” truly captured the enormity of the storm. There were lots of Tweets and posts from folks who exclaimed that Hurricane Patricia was really a category seven hurricane if you were to follow the 20 MPH increments of the current Saffir-Simpson Hurricane Wind Scale beyond its open-ended ending.
Engineer Herbert Saffir and meteorologist Robert Simpson teamed up to develop the eponymous scale in the 1970s as a way to easily communicate to the public the threat a hurricane’s winds pose to structures in the path of a storm. The scale works pretty well—the system is so ubiquitous that you know instantly that a category one hurricane will cause less wind damage than a category four. You know your house would probably stand up to a category one, while you’re taking inventory of your belongings if a category four or five looms offshore.
The biggest criticism of the scale these days is that it only conveys the threat of wind, when storm surge and freshwater flooding from prolific rain are often the most serious hazards with landfalling tropical systems. For example, Hurricane Sandy “only” had category one winds at landfall, and Hurricane Katrina was “only” a category three when it struck the northern Gulf Coast.
It’s rare that we get to entertain the idea of stretching the Saffir-Simpson scale beyond a category five, and thankfully so. It would be counterproductive to add a category six or category seven to the scale. The first reason is that the scale is outdated and we desperately need to develop a new system that can accurately reflect the threat of storm surge and flooding instead of just wind.
Second, category five is labeled “catastrophic” for a reason. Here’s the category’s description from the above-linked page at the National Hurricane Center:
A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
Pretty hard to top that!
Hurricane Patricia was a meteorologically incredible storm that exacted a human toll that was much lower than one would expect from a landfalling category five hurricane. This storm should have done so much more damage than it did—though it destroyed hundreds of lives in a matter of minutes, it made landfall in the one spot where it did the least damage possible.
Hopefully the next time we see a storm of this caliber, it’s far out to sea where it’ll sit, spin, and burn out without so much as a breeze on land.