We are camping in the middle of the Chesapeake Bay on the longest and one of the coldest nights of the year.

South Marsh Island doesn't exactly rise up mightily from the sea. As you pass the northern tip after the eight-mile run from Crocheron, it is at first hard to imagine that this humble lump of wetland is your destination.

But South Marsh goes on and on, the same flat, gray grass lifted barely above sea level. There's not a single tree. You keep hoping for some improvement, but finally it's clear--this is it.

Winter camping is, as a wise man said, hard to get up for. The satisfactions are great but so are the miseries. Back home, in a warm bed with the north wind howling outside, the memory of the miseries always returns first.

We've arrived at South Marsh late, five adventurers from the city in two fast boats. The plan was to get here in early afternoon, scout a campsite, explore the island, fix dinner, build a fire, camp in peace. But stops at pretty places on the Eastern Shore, ice to break at the put-in and the brief confusion over where South Marsh is took a toll in time.

The sun is in orange decline as we scoot along the eastern edge of the island, leaving us with the prospect of making camp by flashlight in 20-degree cold.

Up pops a building on shore--an abandoned hunting club on a tump of marsh grass. We press the throttles down and race for it, hauling the boats the last hundred yards. The water is clear, only a foot deep. We find ourselves kicking oysters that are scattered on the hard bottom. Alan and Robbie snatch up a bucketful to fry later.

At 4:45 on this bright winter day, the sun meets the watery horizon. From the time the giant ball touches down to the time its fiery top disappears is exactly three minutes. The night wind whips from the northwest. The boats are anchored safely in the lee of the island. Quickly it's black, moonless, dark. Six miles across the bay, house lights flicker on in Deal Island.

We're on our own, out of touch with everyone but ourselves.

"Well," says Manuel, smiling, "I certainly didn't expect to find a hotel here."

Scientists say the sea is rising about an inch every 10 years, evidently because of increasing air temperatures and subsequent melting ice. In the lowlands of the Chesapeake the phenomenon is busily eroding away places where people once worked and played.

Such a place is our hotel. The wooden bulkheads that once held off the tides now hang like skeletons over encroaching water. Everything has lost its underpinnings, but the roof and walls hang on, slowing the drafts.

I'm inside a duck-down sleeping bag that is inside a poly-fill bag. I have on three layers of wool socks, four layers of shirts and sweaters, wool trousers and long johns, a wool hat and face mask. I'm still cold.

At 4 o'clock on this fitful morn the bottom falls out of the northwester and it is eerily still. I brave the cold to go outside and stare at a panoply of stars and a sliver of late-rising moon. Orion's Belt looks close enough to toss a snowball at. The chop is gone from the bay. It's flat calm. I realize with a shudder that it's too calm. Our island is locked in a sea of ice.

I remember the waterman who told me once that the coldest hour on the bay is always the last hour before daylight.

We go exploring early, breaking the slushy ice around our hotel with kayaks and canoes we've brought along, but there's not much to see. Every creek and rivulet is frozen. The swans and Canada geese we'd heard in the coves at night have moved offshore to open water. The wary black ducks are gone.

Except for us, a few redwing blackbirds and some muskrats underground, South Marsh seems empty of life.

At 11 o'clock with the tide high, we decide to get out while the getting is good.

The boats crunch through the ice. Within a half-hour we're in open water, waving to the oystermen aboard the Deal Island skipjacks.

Near Crocheron, an oyster tonger beckons me alongside to beg a tow back into harbor. We haul him in and ask to buy some oysters. "Sorry," he says, "I never even got out."

That night we pitched camp on Taylor's Island, which you get to by land. We found the clearing in a pine grove (Taylor's has trees!).

We made a long hike in the woods, finding our way back after dark with the compass. Tom shot at a rabbit but missed.

There were six pounds of beef stew and two loaves of bread for dinner. A slashing combination of rain, sleet and snow assaulted us as we slept, but the tents held up.

We were hungry enough next morning for a massive breakfast and there was time for one more long hike.

We were back in the city by nightfall, sharing a strange euphoria after three days and two nights against the elements.

If somebody asked me to go winter camping tomorrow I'd probably say I was busy all week cleaning my toothbrushes.

Yet a part of me wants to go again. I don't think I'll ever forget that moonrise, or the ice closing in like a giant hand.