Hurricane Otis strengthened from a tropical storm to a dangerous Category 5 hurricane in a matter of hours on Tuesday as it approached Mexico’s southern Pacific coast, with the president urging residents to seek shelter. The storm was forecast to make landfall near the resort of Acapulco early on Wednesday and the US National Hurricane Center warned it will cause catastrophic damage. “A nightmare scenario is unfolding for southern Mexico this evening with rapidly intensifying Otis approaching the coastline,” a National Hurricane Center forecaster said late on Tuesday. “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,” the weather service said. “There are no hurricanes on record even close to this intensity for this part of Mexico.” President Andrés Manuel López Obrador told people via the platform X, formally known as Twitter, “to go to shelters, stay in safe places away from rivers, streams, ravines and be alert, without being overconfident.” In Acapulco, a city of more than a million people, residents hurried home as rain began to pelt the resort and winds picked up, driving tourists from the beach. The Guerrero state government said it was preparing 396 shelters in anticipation of families being driven from their homes by wind damage or surging waters. Mexico’s army and navy deployed more than 8,000 troops to the area with specialised equipment to aid in rescues. Authorities closed Acapulco’s port, home to about 300 fishing boats. Otis was expected to dump five to 13 to 25cm (10in) of rain on Guerrero, with as much as 38cm possible in some areas. That raised the possibility of mudslides and flashfloods in Guerrero’s steep mountainous terrain. The US National Hurricane Center said Otis had maximum sustained winds of 260kph (160mph) late Tuesday and was centred about 90km (55 miles) south-southeast of Acapulco, moving north-northwest at 15kph. Otis was forecast to remain a Category 5 hurricane through landfall but was expected to then rapidly weaken due to the higher terrain of Mexico. The storm will then likely dissipate over southern Mexico on Wednesday night. A hurricane warning was in effect from Punta Maldonado to Zihuatanejo and a hurricane watch is in place from Lagunas de Chacahua to Punta Maldonado Meanwhile in the Atlantic, Hurricane Tammy continued moving northeastward over open water with winds of 120kph after sweeping through the Lesser Antilles over the weekend. The storm was expected to weaken by Thursday, according to the US National Hurricane Center.