Field Guide

Look first for the blow: a tall, bushy column of mist that hangs in the air for a second before it fades. Once you see one, keep watching that same patch of water, because the whale will roll up again, showing a long, dark, knuckly back. The real reward comes on the deep dive, when it lifts that wide tail, the fluke, high out of the water and slides under. Every fluke is patterned a little differently underneath, like a fingerprint.

If we get very lucky, we may see one throw its whole body out of the water in a breach, or a group herding fish with a ring of bubbles. That second one is bubble-net feeding, and Frederick Sound is one of the best places on earth to watch it happen.

Orcas give themselves away with that tall, straight dorsal fin slicing up through the surface, jet black against the gray water. The males carry a fin that can stand as tall as a grown person, while the females and youngsters have a shorter, more curved one. Watch for the crisp white patch behind the eye and the pale saddle just behind the fin as they roll.

They almost always travel as a family group, so if you spot one fin, scan left and right and you will usually find several more rising and falling together. They move with real purpose, and a pod cutting across the channel is one of the great sights of the north coast.

Dall's porpoises are small, stocky, and beautifully marked in crisp black and white, a bit like a tiny orca. You rarely see the whole animal; instead you catch the fast flash of a white side and a burst of spray. When they race at full speed they throw up a fan of water off their backs called a rooster tail, a little splash that follows them along.

The fun part is that they come to us. They love to ride the pressure wave at the bow of a moving ship, darting back and forth just under the surface. If you see quick splashes racing toward the bow, get to the front of the rail.

Sea otters are easy to love and easy to spot once you know the pose: they float on their backs at the surface, often with their paws held up out of the cold water. Look for a small dark shape low in the water, sometimes rolling, sometimes just drifting. A mother may carry a pup riding on her chest, and they will often gather in loose groups called rafts.

Bring the binoculars for this one, because they sit low and can look like a floating log at first. The giveaway is the way they fuss and groom, working air into that famously thick fur.

Steller sea lions pile up on rocky islets and ledges in big, noisy groups called haulouts. Look for a heap of tawny, golden-brown bodies sprawled on the rocks just above the waterline, often with a few big bulls sitting up tall and proud above the rest. They are far larger than the harbor seals, and they have visible little ear flaps and long front flippers they use to prop themselves up.

On the water they swim with their heads up and their chests out, and they bark, growl, and bellow constantly. A rock covered in them is a wonderful, rowdy thing to drift past.

Harbor seals are the round, calm, dog-faced ones. Look for a smooth gray or brown body, speckled with darker spots, resting on a chunk of floating ice or low on a sandbar. Unlike the sea lions, they have no visible ear flaps and they cannot prop up on their flippers, so on land they look like they are lounging on their bellies, sometimes curled into a comma shape with head and tail lifted.

In the water you will usually just see a smooth, whiskery head pop up, watch you for a moment with big dark eyes, and quietly sink away. They are shy and they do not make the racket the sea lions do.

When people picture an Alaska bear, this is the one: a heavy, broad-shouldered brown bear, what most of us call a grizzly, standing in a stream with salmon all around its feet. The giveaway is the muscular hump over the shoulders and a wide, dished face. In July the salmon are running, so the bears come down to the water to feed, and that is exactly when we will be there.

We are most likely to spot one from the ship or a tour boat along a quiet shoreline, or out on the flats where a river meets the sea. Brown bears keep their distance, so a calm scan of the beaches with binoculars is the way to find them.

Black bears are the more common bear of the Southeast Alaska rainforest, and they love the same salmon streams the big browns do. They are smaller and rangier, with a straight face from forehead to nose and tall, pointy ears, and no shoulder hump. Despite the name their coat can be black, brown, or even a deep cinnamon, so go by the shape, not just the color.

Look for them along wooded shorelines and at the edges of streams where salmon are pushing upriver. They are nimble and a little shy, often slipping back into the trees the moment they feel watched.

Down here in the lower 48 a bald eagle is a lucky day. In Southeast Alaska they are almost ordinary, and that never stops being a thrill. Look for the snow-white head and tail against a dark chocolate body, often perched at the very top of a spruce or on a dock piling, just watching the water. In flight they soar on long, flat, plank-straight wings.

Young eagles can fool you: they are mottled brown and white and do not get the clean white head until about five years old. If you see a big brown raptor that looks messy, it may be a young bald eagle growing into its colors.

As we cruise into Glacier Bay, look up. Those small white specks on the steep grey cliffs are not patches of snow; they are mountain goats, picking their way across ledges that seem impossible to stand on. Through binoculars you will see a shaggy white coat, a black nose, and short black horns on both males and females. They have a stocky, hunched look, like they are wearing a heavy winter coat in July.

Gloomy Knob, a rounded rock outcrop in Glacier Bay, is a classic spot to find them; the naturalist on board often points it out. The goats favor the cliffs because almost nothing can reach them up there.

Puffins are everyone's favorite, and for good reason. The tufted puffin has a chunky dark body, a big bright orange bill, and a white face trailing two long golden plumes that sweep back over its head like a fancy hairstyle. They sit low on the water and fly with a fast, buzzy wingbeat that looks almost too quick for such a round little bird.

Watch for them on and around rocky islets where they nest in burrows on the grassy tops. They often raft together on the water near these colonies, bobbing in little groups.

These are the little deer of the Southeast Alaska rainforest, smaller and stockier than the deer we know back home, with a warm reddish-brown summer coat, big rounded ears, and the short black tail that gives them their name. They are quiet browsers, slipping along forest edges and clearings, often half-hidden in the tall summer greenery.

Look for them at the edge where forest meets open ground, especially early and late in the day. In July they are often nose-deep in wildflowers like fireweed, which makes for a sweet sight if you catch one.

It is easy to think of a glacier as just a big frozen lake, but it is really a slow river, and like a river it has a beginning. High up in the mountains, more snow falls each winter than can melt away each summer. That leftover snow piles up year after year, and as new snow buries the old, the buried layers get squeezed. The fluffy flakes are pressed into a grainy, half packed snow called firn, and then, under the growing weight above, the firn is crushed into dense, clear glacial ice.

Here is the part that surprises everyone. Once that ice gets thick enough, its own weight makes it flow. Slowly, stubbornly, the whole frozen mass begins to creep downhill, a river of ice moving so gradually you cannot see it happen but fast enough to grind valleys and carry mountains of rock. Every glacier we will see began as single snowflakes that fell, perhaps, before any of us were born, and have been pressed and pushed downhill ever since.

These are the glaciers that put on the show. A tidewater glacier is a river of ice that has flowed down out of the mountains and reached the ocean, so instead of melting away on land it ends in a sheer cliff of ice standing right in the water. That cliff is the part we come to see. It can rise hundreds of feet straight up out of the sea, taller than it looks until a tour boat or a kayak drifts past for scale and suddenly you understand how big it really is.

Watch the face for a while and you will notice it is alive. Meltwater pours off it, chunks of ice drop from it, and the whole wall groans and cracks as the glacier behind keeps pushing forward. We will sit in front of these for a good while, so let your eyes wander up to where the ice meets the mountains and trace the whole frozen river back to where it began.

Not every glacier reaches the sea. A valley glacier is a river of ice that flows down a mountain valley and ends on land, which means this is the kind you can stand in front of, hike toward, and really get close to. Where a tidewater glacier shows you a wall of ice rising out of the water, a valley glacier lays the whole frozen river out in front of you, curving down between the mountains with the bare rock it has scraped clean on either side.

Because they end on land, valley glaciers often leave behind a glacial lake at their foot, milky and pale from the rock flour the ice has ground to powder. Standing at the edge of that water, looking up the long blue tongue of ice to where it disappears into the high country, is a quieter kind of wonder than the booming glacier faces, and just as moving.

The first time you see it, the blue almost looks fake, like someone tinted it. They did not. Glacier ice glows blue for a beautiful reason: when sunlight sinks into the dense ice, the ice quietly drinks up the red and orange part of the light and lets the blue pass through and scatter back out to your eye. The deeper and more solid the ice, the longer the light travels inside it, the more red gets absorbed, and the richer that blue becomes.

Ordinary ice and fresh snow look white because they are full of tiny trapped air bubbles that bounce every color back at once. Glacier ice is different. It has been buried and squeezed for so long that the air has been pressed out and the crystals have grown large and clear, so the blue can finally show. The most electric blue often hides in fresh cracks and in the ice that has just calved off, where you are seeing deep old ice for the very first time.

This is the moment everyone hopes for. Calving is when a slab of ice breaks off the front of the glacier and crashes into the water, and when it happens the whole face seems to come alive. The Tlingit people called the sound white thunder, and that is exactly right: a deep boom and crack that rolls across the water and that you feel as much as hear.

Here is the trick to actually catching it, and it surprises everyone. Sound travels much slower than light, so by the time the boom reaches you across the water, the ice has already fallen. If you wait for the crack you heard, you will be looking at the wrong spot and you will miss it. So do not watch the noise. Keep your eyes soft and wide on the whole ice face, watch the water at the base for sudden splashes and ripples, and let the booms be a signal to keep looking, not a place to look.

Once a glacier calves, the ice it dropped goes drifting off across the fjord, and sailors long ago gave the pieces names by size. The big ones, taller than about 16 feet out of the water, are icebergs. The medium pieces, roughly the size of a small house, are bergy bits. The little ones, only a few feet across and about the size of a truck or a piano, are called growlers, named for the low gurgling, hissing sound they make as trapped air escapes and the water laps around them.

Whatever the size, the same rule holds: what you see is only the tip. Ice is just a little lighter than seawater, so about 90 percent of every berg sits hidden below the surface and only a tenth shows above. That floating chunk that looks small from the deck is far bigger than it lets on, which is exactly why even the little growlers are taken seriously by anyone steering a boat.

Look closely at a glacier and you will often see dark stripes running down its length, like racing lines on the white ice. Those are moraines, and they are made of real rock and rubble. As a glacier grinds down its valley it tears stone loose from the walls and the ground, and it carries all of that debris along, sometimes for miles, the way a slow conveyor belt carries whatever lands on it.

The stripes along the two edges of the glacier are called lateral moraines, the rock it has scraped off the valley walls on either side. The really striking ones are the dark lines running right down the middle. Those form when two glaciers flow together and meet, like two lanes of traffic merging, and the rocky edges they each carried get pinched into a single stripe down the center. So when you trace a dark line up the ice, you are usually looking at the seam where two rivers of ice became one.