If a storm is a Category 3, 4 or 5, it is deemed a "major" hurricane due to the potential for "significant loss of life and damage," the National Hurricane Center says. Hurricanes that fall into categories 1 or 2 are still considered dangerous, the center says.

Hurricane Erin became the first hurricane of the 2025 Atlantic season on Friday, with sustained winds of 75 mph as it moves toward the Leeward Islands.

Maximum sustained winds have increased to near 140 mph, with higher gusts. Erin is a Category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Some additional strengthening is expected today. Erin will remain a dangerous major hurricane through the middle of this week.

The longstanding hurricane rating system, the Saffir-Simpson Scale, only takes into account sustained wind speeds and not the full devastating impact of a hurricane.

Let's break it down. Big Picture -What It Measures: As the name implies, the current version is strictly a wind scale that rates a hurricane's sustained winds (not gusts) from Category 1 through 5.

Hurricane Erin weakened to a Category 3 storm with maximum sustained winds of 125 mph as its outer bands pounded the Virgin Islands and Puerto Rico with gusty winds and heavy rains Sunday. The U.S. East Coast is forecast to have rough ocean conditions through the middle of the week as the storm strengthens,