ReutersHurricane Erin, which is the first hurricane of the 2025 Atlantic season and has developed into a dangerous Category 4 hurricane, moves westward near Puerto Rico in a composite satellite image August 16, 2025. CIRA/NOAA/Handout via REUTERS THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY Hurricane Erin exploded and strengthened into a Category 5 hurricane over the Atlantic Ocean on Saturday (August 16, 2025) before weakening slightly to a Category 4 status. However, it remained a "formidable" storm while it underwent a process known as an "eyewall replacement cycle," the National Hurricane Center in Miami said. The first Atlantic hurricane of 2025, Erin, reached Category 5 status before weakening somewhat and becoming a Category 4 storm, with maximum sustained winds of 140 mph (220 kph). "Some fluctuations in intensity are expected over the next couple of days due to inner-core structural changes," the Miami-based hurricane center said, as quoted by CBS News. A Category 4 hurricane has maximum sustained winds of 130 mph or higher. Late at night, the center reported that Erin was “undergoing structural changes” but was still “formidable” as its rain and winds buffeted Puerto Rico and the Virgin Islands. The storm’s center was about 145 miles (230 kilometers) north-northeast of San Juan, Puerto Rico, and it was heading toward the west-northwest at 14 mph (22 kph). It was not forecast to make a direct hit on land.Hurricane center director Mike Brennen said Erin grew into a “very powerful hurricane,” with its winds gaining 60 mph (96 kph) in about nine hours. Forecasters predicted that it would remain a major hurricane into the coming week.Forecasters urged people in the Caribbean islands to monitor Erin's progress. According to CBS News, they warned of the potential for heavy rainfall and life-threatening surf and rip current conditions.Live EventsWhat is an eyewall replacement cycle?The hurricane center on Saturday night (August 16, 2025) revealed that Erin was undergoing an "eyewall replacement cycle." According to CBS News, it is a situation when the storm has become so significantly powerful that its eyewall, its strongest part, attains maximum strength.As soon as this happens, the eyewall itself becomes so intense from intaking the available energy from its environment that a new eyewall starts to build on the outside of the existing, inner eyewall. Once the new eyewall is formed, it cuts off the fuel to the original eyewall and eventually leads to its demise. This process may cause the storm to weaken temporarily, and its wind speeds may slow as it regains strength.Hurreicane Erin: Map reveals forecast pathErin's path continued to curve northward, with the center of the hurricane passing just to the north of the northern Leeward Islands and Puerto Rico. The northern Leewards stretch from the Virgin Islands to Guadeloupe and include St. Martin, St. Barts, and other islands. Officials had issued tropical storm watches for several islands, alerting people to the possibility of winds ranging between 39 mph and 73 mph.Erin’s path continued curving northward, with the hurricane’s center passing just north of the northern Leeward Islands and Puerto Rico. The northern Leewards, stretching from the Virgin Islands to Guadeloupe, include islands like St. Martin and St. Barts, among others. Officials issued tropical storm watches for several islands, warning residents of possible winds between 39 and 73 mph.According to a "spaghetti map" of the forecast models, the storm can be seen skirting the Caribbean islands and remaining well offshore of the U.S. East Coast as it moves north, CBS News reported.Hurricane Erin close enough to land to trigger flooding, landslidesAccording to the National Hurricane Center, the storm's center was forecast to pass north of Puerto Rico. The Centre stated that heavy rain in some areas could trigger flash flooding, landslides, and mudslides, news agency AP reported. Tropical storm watches were issued for St. Martin, St. Barts, and the Turks and Caicos Islands. The National Weather Service in San Juan issued an alert for Saturday night for nearly two-thirds of Puerto Rico, warning of 50 mph (80 kph) winds and urging people to shelter in safe structures. Power was knocked out to about 130,000 customers in the territory.Locals and tourists walked, exercised, and shopped as usual earlier in the day in the Puerto Rican capital, according to AP. Restaurants were busy, and despite warnings to avoid beaches, people could be seen in the water. Parents kept their children from swimming, however. Sarahí Torres and Joanna Cornejo, who were visiting from California for a Bad Bunny concert, said they decided to go to the beach and wade in because the skies were calm. “The weather looked fine, so we came out,” Torres was quoted by AP as saying. The U.S. government deployed more than 200 employees from the Federal Emergency Management Agency and other agencies as a precaution. Puerto Rico Housing Secretary Ciary Pérez Peña said 367 shelters were inspected and ready to open if needed.Officials in the Bahamas also prepared shelters and urged people to monitor the storm's progress. Powerful rip currents could affect the U.S. East Coast from Florida to the mid-Atlantic next week, despite the eye of the storm forecast to remain far offshore, Brennan said. An ‘incredible’ race from tropical storm to Category 5Hurricane specialist and storm surge expert Michael Lowry said Erin gained strength at a pace that was “incredible for any time of year, let alone Aug. 16.” Lowry said only four other Category 5 hurricanes have been recorded in the Atlantic on or before August 16. The most powerful storms tend to form later in the year (2025), with the hurricane season typically peaking in mid-September.Hurricanes Erin and 42 other hurricanes have reached Category 5In October 2005, Hurricane Wilma rocketed from a tropical storm to a Category 5 in less than 24 hours, according to National Hurricane Center advisories from that time. Wilma weakened to a Category 3 hurricane before striking Florida. And in October 2007, Hurricane Felix took just over a day to go from a tropical storm to Category 5.Including Erin, there have been 43 hurricanes that have reached Category 5 status on record in the Atlantic, said Dan Pydynowski, senior meteorologist at AccuWeather, a private forecasting company, according to AP. “They’re certainly rare, although this would mark the fourth year in a row that we’ve had one in the Atlantic basin,” Pydynowski said. Conditions needed for hurricanes to reach such strength include very warm ocean water, little to no wind shear, and being far from land, he said.Erin is the fifth named storm of the Atlantic hurricane season, which runs from June 1 to Nov. 30 and is expected to be unusually busy. Six to 10 hurricanes are predicted for the season, including three to five reaching major status with winds of more than 110 mph (177 kph).(You can now subscribe to our Economic Times WhatsApp channel) Read More News onHurricane Erinnational weather serviceEyewall Replacementnational hurricane centererin (Catch all the US News, UK News, Canada News, International Breaking News Events, and Latest News Updates on The Economic Times.) Download The Economic Times News App to get Daily International News Updates....moreless (You can now subscribe to our Economic Times WhatsApp channel)Read More News onHurricane Erinnational weather serviceEyewall Replacementnational hurricane centererin(Catch all the US News, UK News, Canada News, International Breaking News Events, and Latest News Updates on The Economic Times.) Download The Economic Times News App to get Daily International News Updates....moreless Explore More Stories123