Under the cover of an operation named Snowbird, agents of the U.S. Customs Service seized almost 100,000 pounds of marijuana being smuggled into Florida in a two-week period last January.

Besides the marijuana, Customs agents grabbed four ships, five aircraft and 18 cars, trucks and vans smuggling drugs into Florida. Seven aliens accused of the smuggling were deported and 50 Americans were arrested in the biggest single operation of its kind conducted by Customs.

"Snowbird was one of the best, if not the best, special enforcement operation we've ever conducted," one Customs agent said.

With a force of agents double its normal size, Customs agent in Florida swooped down on aircraft landing at clandestine fields and ships moving into little-used marinas in the last two weeks of January. The first ship that agents boarded in Miami harbor was concealing 50 pounds of cocaine, with a street value of $15 million.

The largest single seizure of marijuana in Snowbird was 23,500 pounds of marijuana aboard a 57-foot Chris Craft yacht in Florida's Inland Waterway. Agents had noticed the yacht riding unusually low in the water and listing to one side.

Another time, the Coast Guard seized off the East Coast of Florida a ship that had detachable nameplates. It also had 300 packing boxes identified as television sets that were actually filled with marijuana.

One seizure involved four tons of marijuana stacked in 50- and 60-pound bales stord above the deck of a ship coming into Tampa. Another involved 2,400 pounds of marijuana airdropped by accident into the Gulf of Mexico alongside an island. Customs agents found the marijuana floating in the water next to the island.

The smallest of five airplanes seized by Customs was a twin-engined Cessna, the largest a DC-4. One of the four ships seized was an island freighter 120 feet long.

"None of the ships was trying to hide its cargo," one Customs agent said. "A few carried bananas in addition to the marijuana, the others carried only the marijuana."