Otis — 2023

A tropical disturbance that formed along the eastern North Pacific monsoon trough developed into a tropical depression on 22 October 2023 about 465 nautical miles south-southeast of Acapulco, Mexico, and became Tropical Storm Otis six hours later. Otis moved generally north-northwestward toward the southern Mexican coast and underwent an extraordinary period of rapid strengthening beginning early on 24 October. The cyclone reached its peak just offshore on 25 October and then moved ashore near Acapulco before weakening quickly over the rugged terrain and dissipating later that day. Otis made landfall in the Acapulco metropolitan area in the state of Guerrero around 0645 UTC on 25 October 2023. At landfall it is estimated to have had maximum sustained winds of 140 knots (161 mph), corresponding to a Category 5 hurricane on the Saffir–Simpson scale. The system weakened rapidly inland, was a tropical storm by 1800 UTC on 25 October, and dissipated soon after. The hurricane’s maximum estimated intensity was 145 knots (167 mph) with an estimated minimum central pressure of 922 mb (best estimate at 0300 UTC 25 October). The record of rapid strengthening shows Otis increased by about 90 kt in 21 hours, making it one of the fastest-intensifying storms on record in the eastern Pacific; its landfall intensity of 140 kt makes it the strongest landfalling hurricane in the eastern Pacific basin since 1988 (when NHC took operational responsibility). Otis produced heavy rain and catastrophic coastal flooding near the landfall area. Measured storm-tide and surge records that captured the peak surge are incomplete, but aerial imagery and on-the-ground observations show devastating storm surge and large breaking waves around Acapulco and nearby coastal communities; many boats and marinas were destroyed in Acapulco Bay and Puerto Marqués Bay. Rainfall totals included 10.47 inches (266.0 mm) in Acapulco, 9.82 inches (249.4 mm) at El Veladero, 8.66 inches (220.0 mm) at Tierra Colorada (Guerrero), and 5.75 inches (146.1 mm) at El Dique Pescaditos in Oaxaca, producing flash flooding, river flooding, and landslides across Guerrero (including Coyuca de Benítez). Official counts report at least 52 deaths attributed to Otis, with an additional 32 people reported missing at the time of the report; most fatalities occurred in and around Acapulco from the storm’s extreme winds, surge, and landslides. Damage estimates from various firms place losses at roughly $12–16 billion (USD), making Otis the costliest tropical cyclone on record for Mexico. Over 250,000 homes in Guerrero were affected (more than 51,000 destroyed and about 80,000 severely damaged), thousands of businesses were damaged or lost, major damage occurred to power and water infrastructure, and hundreds of thousands of residents were left without electricity or water service. Noteworthy aspects include the storm’s historic and unexpected rapid intensification—about a 90-kt increase in 21 hours—which greatly exceeded intensity guidance and resulted in unusually large intensity forecast errors. Reconnaissance aircraft and high-resolution satellite retrievals showed Otis was stronger than many routine satellite estimates indicated during the rapid intensification. Forecasts did provide several days’ lead time on the disturbance’s genesis and issued watches and warnings more than 20 hours before tropical-storm-force winds arrived in Acapulco, but the extreme final intensification and resulting catastrophic impacts were not anticipated by most models or operational intensity forecasts.