Hurricane Otis was a compact but very powerful tropical cyclone that made a devastating landfall near the Mexican city of Acapulco as a Category 5 hurricane in October 2023. Otis was the first Pacific hurricane on record to make landfall at Category 5 intensity and became the strongest Pacific hurricane to make landfall, surpassing Hurricane Patricia of 2015. The resulting damage made Otis the costliest tropical cyclone to strike Mexico on record, surpassing Hurricane Wilma of 2005. The fifteenth tropical storm, tenth hurricane, eighth major hurricane, and second Category 5 hurricane of the 2023 Pacific hurricane season, Otis originated from a disturbance several hundred miles south of the Gulf of Tehuantepec. Initially forecast to stay offshore and to only be a weak tropical storm at peak intensity, Otis instead underwent explosive intensification to reach peak winds of 165 mph (270 km/h) and weakened only slightly before making landfall as a powerful Category 5 hurricane. Once inland, the hurricane quickly weakened before dissipating the following day.
Making landfall just west of Acapulco, Otis's powerful winds severely damaged many of the buildings in the city. Landslides and flooding resulted from heavy rain. Communication was heavily cut off, initially leaving information about the hurricane's impact largely unknown. In the aftermath, the city had no drinking water and many residents also lost power. The government of Guerrero mobilized thousands of military members to aid survivors and assist in recovery efforts. Thousands of recovery items were sent out to those affected and donations were sent out to each of the affected families.
The hurricane caused at least 52 deaths and left 32 others missing. Total damage from Otis was estimated to be in the billions of dollars (2023 USD), with several agencies estimating $12–16 billion in damage, making it the costliest Pacific hurricane on record, surpassing Hurricane Manuel in 2013.
Meteorological history
On October 15, 2023, the National Hurricane Center (NHC) noted that an area of low pressure was expected to form several hundred miles south of southeastern Mexico over the next seven days. This forecast came to fruition on October 18 with the development of a broad low several hundred miles south of the Gulf of Tehuantepec. Accompanied by disorganized convection, organization into a tropical cyclone was deemed likely within five days as the system meandered in the same general area. Convection grew in scope the following day, though upper-level wind shear displaced this to the west of the system's center. Throughout October 21, convection increased in coverage and the system's surface circulation became more defined. The disturbance's meandering motion shifted to a northward crawl as it was wedged between a ridge to the northeast and a trough to the northwest. Following further convective organization, the system became Tropical Depression Eighteen-E at 12:00 UTC (07:00 a.m. CDT) on October 22. At this time, the depression was situated roughly 535 mi (860 km) south-southeast of Acapulco, Mexico. Six hours later, the system intensified into a tropical storm, at which time it was assigned the name Otis.
Light to moderate southeasterly wind shear displaced convection northwest of Otis's surface circulation during the overnight hours of October 22–23. The lack of vertical alignment and dry mid-level air delayed potential intensification despite an otherwise favorable environment consisting of high sea surface temperatures and abundant atmospheric moisture. Sea surface temperatures ahead of the system averaged 86–88 °F (30–31 °C), above average for this time of year. The high temperatures resulted from a combination of a record-warm September for Mexico, an ongoing El Niño, and the influence of global warming. The system's motion shifted from due north to north-northwest during this time, remaining around 4–5 mph (6–8 km/h). A convective band developed halfway around the storm by the afternoon of October 23, and the surface circulation and thunderstorm activity moved closer together. During the overnight of October 23–24, the storm moved into a region of more favorable conditions, with higher sea surface temperatures and weaker vertical wind shear. Microwave satellite imagery depicted a low-level ring structure, often a precursor to rapid intensification, despite the overall sheared appearance of the system. The storm's forward motion also increased during this time, potentially offsetting the negative impacts of southeasterly wind shear. As a result, upper-level outflow expanded noticeably and the system's core became centered in the convection. This led to Otis beginning an explosive intensification phase that would continue until just before landfall. As the morning of October 24 progressed, outflow continued to expand in all directions atop Otis and many banding features circulated the storm. The improvement in outflow was accentuated by a powerful jet streak—a wind maxima within the jet stream—which accelerated the rate of latent heat dispersal and fostered convective development. Otis commenced explosive intensification and became a hurricane by 12:00 UTC (07:00 a.m. CDT) on October 24.
Shortly after 18:00 UTC (1:00 p.m. CDT), the only Air Force Reserve Unit Hurricane Hunter mission flown into Otis penetrated its eye, and the observations indicated that Otis had already reached Category 3 intensity and thus become a major hurricane. This was substantially above estimates using the Dvorak technique, which ranged from only 70 mph (110 km/h) to 105 mph (165 km/h); Otis was persistently stronger than indicated by the Dvorak technique throughout the rapid intensification phase. Operationally, the NHC had only upgraded Otis to a Category 1 hurricane on the Saffir-Simpson scale. Explosive intensification continued throughout the day into the nighttime hours, in what was described as a "nightmare scenario" by Eric Blake at the NHC. A prominent pinhole eye developed as the night progressed, surrounded by intense convection reaching −103 to −112 °F (−75 to −80 °C). Otis reached its peak intensity as a Category 5 hurricane with maximum sustained winds of 165 mph (270 km/h) and a minimum central pressure of 922 mb (27.23 inHg) at 03:00 UTC on October 25 (10:00 p.m. CDT, October 24)–just nine hours after attaining Category 3 intensity–while located just 60 mi (95 km) south-southeast of Acapulco. Immense lightning activity occurred throughout the intensification phase, approximately 26,000 strikes in 24 hours, with the greatest activity taking place in the 55 minutes leading up to landfall. As Otis neared landfall, satellite images showed some cooling and filling in of the eye, suggesting that the storm weakened slightly before landfall. By 05:45 UTC (12:45 a.m. CDT), Isla de La Roqueta entered the hurricane's eyewall and the storm's core made landfall just west of Acapulco around 06:45 UTC (1:45 a.m. CDT) just below peak intensity, though still at Category 5 intensity, with winds of 160 mph (260 km/h) and a minimum central pressure of 929 mb (27.43 inHg). Once onshore, the hurricane rapidly weakened as it interacted with the mountains of the Sierra Madre del Sur. Within two hours, its eye disappeared from satellite imagery and lightning activity ceased. Utilizing statistical inland decay models, the NHC estimated Otis to have fallen below hurricane status by 18:00 UTC (1:00 p.m. CDT). The storm's surface circulation dissipated shortly thereafter, marking the cessation of Otis's time as a tropical cyclone.
Forecast errors and distinctions
The rapid intensification of Otis was among the most poorly forecast in the modern era. Meteorologists Jeff Masters and Bob Henson at Yale University called the underestimation "one of the biggest and most consequential forecast-model misses of recent years". Numerical weather prediction models failed to capture the magnitude of explosive intensification that occurred, in part due to a dearth of data. Several experts, including director of the National Hurricane Center Michael Brennan, noted that there are very few instruments — such as ocean buoys or radar — available for evaluating hurricane strength in the East Pacific, leaving forecasters reliant on satellite data. As described by The New York Times, forecasts of Otis upon its formation on October 22 "didn’t show much to be concerned about". In their first advisory, the NHC forecast a peak intensity of just 45 mph (75 km/h), 120 mph (195 km/h) lower than its actual peak intensity, with the system moving north-northwest and later west away from the Mexican coastline. Forecasters John Cangialosi and Lisa Bucci noted that many models showed the storm outright dissipating within five days.
Early on October 23, Blake noted that models were incorrectly diagnosing conditions and showing Otis intertwined with the Intertropical Convergence Zone. He adjusted his forecast to show a faster motion which would bring the system onto the Mexican coastline on October 26. Later that day, forecasters Cangialosi and Sandy Delgado noted a substantial disparity in various model solutions, with results differing based on how vertically aligned the storm would become or not become. Conditions for a more potent system became more apparent during the overnight hours of October 23–24. This included high sea surface temperatures, lower wind shear, and abundant moisture. The system also became vertically aligned. The Statistical Hurricane Intensity Prediction Scheme (SHIPS) rapid intensification index increased to 25 percent, leading forecasters to raise their intensity predictions above most model outputs. At 09:00 UTC (4:00 a.m. CDT) on October 24, less than 24 hours before landfall, the NHC expected Otis to intensify into a Category 1 hurricane as it moved ashore. Sixteen hours prior to landfall, the system was forecast to move ashore at least five hours later than it actually did. The dramatic rate of intensification was not apparent until reconnaissance aircraft sampled the storm during the afternoon of October 24. At 00:00 UTC on October 25 (7:00 p.m. CDT, October 24), just under six and a half hours before the storm made landfall, the NHC upgraded Otis to a Category 4 hurricane and explicitly forecast it to become a Category 5 hurricane before making landfall.
The rate of Hurricane Otis's intensification was among the fastest observed in the satellite era. In a 21-hour period, the hurricane's maximum sustained winds increased by 105 mph (165 km/h), ranking it as the second-fastest in the basin, only behind Hurricane Patricia in 2015, which increased by 120 mph (195 km/h) in a period of 24 hours. With winds of 160 mph (260 km/h), Otis became the first Pacific hurricane on record to make landfall at Category 5 intensity, surpassing Hurricane Patricia accordingly. Overall, it was tied with Hurricane Gilbert of 1988 in the Atlantic as the fourth-strongest landfalling Mexican hurricane by sustained wind speed, behind the following Atlantic hurricanes, each with sustained winds of 175 mph (280 km/h): Janet in 1955, Anita in 1977, and Dean in 2007. Masters and Henson surmised Otis's landfall saw the most people impacted by the eyewall of a Category 5 hurricane. They further stated the only hurricane of comparison was Hurricane Andrew in 1992, which struck the Miami metropolitan area at Category 5 strength (producing such winds in parts of southern Miami-Dade County).
Preparations
The Government of Mexico issued a tropical storm warning and a hurricane watch for areas east of Tecpan de Galeana to Lagunas de Chacahua at 03:00 UTC October 24. As the storm approached land and intensified further, a hurricane warning was issued for the Guerrero coastline between Punta Maldonado and Zihuatanejo at 09:00 UTC October 24, 21 hours before landfall. In response to the approach of Hurricane Otis, the Guerrero state government opened 396 shelters to accommodate residents displaced by the heavy wind and storm surge damage. Mexico's army and navy sent 8,000 troops to support aid and rescue operations. Authorities in Guerrero closed Acapulco's main port. Schools across Guerrero were to be closed ahead of Otis's anticipated landfall. All flights in and out of Acapulco International Airport were cancelled.
In its advisory upgrading Otis to a Category 5 hurricane, 3 hours and 45 minutes before landfall, the NHC described the situation as a "nightmare scenario" and warned that "This is an extremely serious situation for the Acapulco metropolitan area with the core of the destructive hurricane likely to come near or over that large city early on Wednesday. There are no hurricanes on record even close to this intensity for this part of Mexico".
Impact
Hurricane Otis made landfall in Acapulco as a Category 5 hurricane on October 25, making it by far the strongest hurricane to ever strike this area of Mexico. On October 30, the National Autonomous University of Mexico tweeted that data from two weather stations in Acapulco Bay were recovered. One station measured peak sustained winds of 113.64 mph (182.88 km/h) with a gust to 204.90 mph (329.76 km/h) at 05:40 UTC (12:40 a.m. CDT). If verified, this would be the seventh highest anemometer-measured wind gust recorded worldwide. A minimum pressure of 963.5 mb (28.45 inHg) was also observed at 05:50 UTC (12:50 a.m. CDT). A weather station on Isla de La Roqueta offshore western Acapulco recorded a maximum wind gust of 135 mph (217 km/h) as the eyewall moved across the city. Peak sustained winds of 82 mph (132 km/h) were also reported by the station. The storm surge was catastrophic near and east of the point of landfall, but a lack of tide station data prevented a quantitative estimate of the height.