If the winds are calm, we make our way across Lowell Lake to where the Lowell Glacier ends. The lake is teeming with icebergs that have calved and fallen off the glacier on the other end of the lake. It's a spectacular sight to raft through these glacier chunks, and listen and watch the glacier's movement through the night.

Launch the rafts into the river and navigate through the icebergs at the snout of the Lowell Glacier. Take in this surreal scene as the icebergs calve off the glacier and float in this lake-like section of the river. The river picks up speed dramatically as it begins to cut through narrower canyons and increase in volume.

Take easy routes through some of the rapids; by mid-afternoon, though, encounter "Lava North," a challenging section of Class IV whitewater that's fun and thrilling. Our guides will scout the rapid beforehand and determine the best route through.

For the next few days the water is swift with continuous small rapids as the river cuts through the Alsek Range. Watch the scenery and look out for wildlife such as grizzly bear, moose, wolf, muskrat, wolverine, mink, snowshoe rabbit, hoary marmot, and Alaska red fox, along with numerous bird species. Reach the Tweedsmuir Glacier with its Turn Back Canyon, filled with sharp drops and horrendous currents.

Prepare the gear for transport, and board a helicopter for a short flight to the gravel flats south of the canyon. From the chopper see every hairpin turn and the churning water crashing into the canyon walls. The scenery changes on the other side - the river is wider, there are numerous braided channels and more vegetation, and bald eagles perch along the mossy cliffs of the Icefield and Noisy Ranges. Relaunch the rafts and drift through the wide valley towards the majestic confluence of the Tatshenshini and Alsek rivers.

Continue down the river through deep forested canyons toward the coast. On the southern horizon, a dozen glaciers flow down from the Fairweather Range, while the Alsek disappears back to the north and east into the symmetrical peaks and waterfalls of the Noisy Range. To the west, the main channel of the Alsek flows into the Fairweather Range, where it seems to sink into the forest. The river below its confluence with the Tatshenshini is a vast, gravel flat, braided with channels and ringed with willow, birch, and alder forests.

Closer to the Gulf of Alaska, the climate becomes more maritime and the glaciers more numerous. Farther down the river, pass the Walker Glacier, which has sprawled down its valley and is visible from the river. Its blue and white shape dominates the view for quite some time.

Continue to float towards Alsek Lake, spotting many species of birds, including bald eagles, semi-palmated plovers, spotted sandpipers, northern phalaropes, American pipits, and more.

Watch and listen as giant chunks of ice calve into the water from the 7-mile face of the Alsek glacier. Some icebergs are 75-feet high, indicating a depth below the surface at least twice as great. The guides will row among ice floes sculpted into bizarre, fluted, ever-changing phantasmagoric shapes - a veritable "iceberg garden."

After floating into the flat, forested plains beyond Alsek Bay, arrive at the Dry Bay Fishing Company outpost along the estuary of the Alsek River. Board a small aircraft for a spectacular charter flight to Yakutat in time for the scheduled Alaskan Airlines service to Juneau (the trip is tailored around this flight, and Juneau is your gateway city to other destinations).