Delta teams are finalizing operational plans as yet another hurricane, expected to bring "devastating to catastrophic impacts" according to the National Weather Service, bears down on the Caribbean.

Hurricane Maria is expected to hit the Virgin Islands and Puerto Rico overnight Tuesday-Wednesday. Delta will continue flying to San Juan all day Tuesday from its hubs in Atlanta and New York, and has added three extra flights above its normal flight schedule to allow residents and visitors more opportunities to evacuate. Delta flights to St. Thomas remain canceled due to the approaching storm and infrastructure constraints caused by Hurricane Irma.

"Our teams throughout the Caribbean are working diligently to ensure a safe operation for our customers ahead of Hurricane Maria," said Luciano Macagno, Delta's Managing Director— Latin America and the Caribbean. "We're doubling the number of flights from San Juan to Delta's Atlanta hub today and operating late into the evening to provide our customers and employees a chance to get out of the hurricane's way."

Delta has capped Main Cabin, one-way nonstop fares at $199 for flights departing San Juan, Punta Cana, Santiago and Santo Domingo through Sept. 21 and is temporarily waiving baggage and pet in cabin fees for customers traveling to and from San Juan and several other airports in the region. See delta.com for a full list.

A travel waiver has been issued for passengers flying out of San Juan from Sept. 19-26. The waiver, which allows customers to change plans without incurring a fee, also covers customers from St. Maarten, St. Thomas, and Turks and Caicos with tickets issued from Sept. 5 to Dec. 31. Delta advises customers to visit delta.com to check the status of booked flights to the region.

An operational restart in St. Thomas and Puerto Rico is planned for Thursday, but is dependent on infrastructure damage assessments after the storm passes. Flights to St. Maarten are expected to resume Saturday, pending further evaluation of airport and surrounding facilities after hurricanes Irma and Maria.

Limited flights to Key West Airport, which has been closed since Hurricane Irma battered the Florida Keys, are expected to resume Wednesday.