How Hurricane Erin exploded in strength and became a major Atlantic hurricane

CBS News

4 hours ago

Erin has strengthened into a powerful Category 5 hurricane in the Caribbean, the National Hurricane Center said Saturday.
The hurricane is not forecast to hit land, but strong winds are affecting nearby islands, prompting forecasters to warn of possible flooding and landslides. The storm will eventually swerve away from the continental United States, the Miami-based hurricane center said.
Erin began as a tropical storm, became a hurricane Friday and quickly intensified overnight Saturday. Here's how the storm became so powerful.
On Friday morning, Erin was only a tropical storm. It underwent rapid intensification, which means the storm's maximum sustained winds strengthened at least 58 miles per hour in a 24-hour window, overnight.
Erin has low wind shear and a tight, compact core. Those features, combined with its path over very warm water, create the "perfect conditions for rapid intensification," said CBS News weather producer David Parkinson. Sea surface temperatures over 85 degrees Fahrenheit and warmer than normal.
Tropical storm watches are in place for St. Martin and St. Barthelemy and Sint Maarten. Up to 4 inches (10 centimeters) are expected, with isolated totals of up to 6 inches (15 centimeters), according to the National Hurricane Center in Miami.
"Locally, considerable flash and urban flooding, along with landslides or mudslides, are possible," the NHC said.
Hurricane specialist and storm surge expert Michael Lowry said Erin is forecast to eventually take a sharp turn northeast that would put it on a path between the U.S. and Bermuda.
"All of our best consensus aids show Erin turning safely east of the United States next week, but it'll be a much closer call for Bermuda, which could land on the stronger eastern side of Erin," he said.
The U.S. government has deployed more than 200 employees from the Federal Emergency Management Agency and other agencies to Puerto Rico as a precaution as forecasters issued a flood watch for the entire U.S. territory from late Friday into Monday.
Puerto Rico Housing Secretary Ciary Pérez Peña said 367 shelters have been inspected and could be opened if needed.
The U.S. Coast Guard said Friday that it closed six seaports in Puerto Rico and two in the U.S. Virgin Islands to all incoming vessels unless they had received prior authorization.
Meanwhile, officials in the Bahamas said they prepared some public shelters as a precaution as they urged people to track the hurricane.
"These storms are very volatile and can make sudden shifts in movement," said Aarone Sargent, managing director for the Bahamas' disaster risk management authority.
Erin formed as a tropical storm on Monday west of the island nation of Cabo Verde, a few hundred miles off Africa's western coast. It is the fifth named storm of the 2025 Atlantic hurricane season, which started June 1 and runs through November 30.
Tropical Storm Chantal is the only one storm to have made landfall in the U.S., bringing deadly flooding to North Carolina in early July. In June, Barry made landfall as a tropical depression on Mexico's eastern coast.
Forecasters could see conditions were ripe for Erin to become an extremely powerful storm as it moved across very warm waters in the open Atlantic. "Water temperatures at the surface and hundreds of feet deep are several degrees higher than the historical average," said Alex DaSilva, Accuweather's lead hurricane expert.
This year's season is once again expected to be unusually busy. The forecast calls for six to 10 hurricanes, with three to five reaching major status with winds of more than 110 mph (177 kph).