Sep. 18--In Key West, skippers awoke the past few days to find docks at Garrison Bight awash. In a stretch of Fort Lauderdale's beach north of Sunrise Boulevard, the sand between the Atlantic and A1A shrank to a narrow strip.

And in Miami Beach, the streets became flooded as salty water flowed up from storm drains along Alton Road.

It's not global warming. It's not from a tropical deluge. And it only lasts a few hours, waning with the tide.

For the past few days and the next few, South Florida is experiencing the effects of a perigean spring tide, a confluence of lunar events that add up to really big tides.

"This particular incident I wouldn't attribute to climate change," said Robert Molleda, a meteorologist with the National Weather Service in Miami-Dade County.

The alignment of moon and earth in the fall always triggers strong tides in South Florida. A new moon Friday will produce this month's maximum flow. On top of that, the moon was at perigee on Wednesday, or its closet point to Earth this month.

"That enhances the spring tides," said Jon Rizzo, a Weather Service meteorologist in Key West.

The result: Several days of higher high tides -- a foot above normal in some spots.

That wouldn't raise an eyebrow farther north, but it is hard to miss in South Florida -- particularly on coastal barrier islands like Miami Beach.

BEACH UNDER WATER

With the city's lowest point near Alton Road and 10th Street sitting 2.8 feet above sea level, it's easy to calculate what happens when tides reach 3.4 feet above sea level. A storm system intended to drain rain into surrounding waters instead pushes surrounding waters into the streets.

Miami Beach has slogged through serious and expensive floods over the last few years.

Last September, similar tidal-driven flooding stalled cars and created block-sized puddles, mostly in the Flamingo Park neighborhood of South Beach. In June, a storm dumped seven to nine inches of rain on the city, closing causeways and leaving The Fontainebleau with ankle-deep water in its night club.

Assistant City Manager Hilda Fernandez and city engineer Fernando Vasquez said the city is doing all it can with its antiquated drainage system. Workers are cleaning out pipes and outfalls and targeting problem areas for improvements. The city also is spending $1 million to study how to overhaul the entire system, projects that will easily cost 100 times more.

IT COULD BE WORSE

Until bigger pipes and more pumps are in place years from now, Fernandez acknowledged, there are limited options to deal with the impact of lunar alignments.

"We are an island," she said. "There are only so many places for the water to go."

Fortunately, forecasters said, other factors aren't worsening things. Thunderstorms, high winds or hurricanes could dramatically increase flooding -- particularly along beaches.

"There is very little wind right now," Rizzo said. "It's nice to not have much surf."

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