Geology in Action

You here over and over, Alaska is a very geologically active area. That's certainly true, but you don't usually witness it except during a volcanic eruption or earthquake. This summer i was able to witness some impressive rockslides during the 'ol 26 Glacier Cruise in Prince William Sound.

I was taking some friends on the tour, and while everyone else was looking at the approach of Surprise Glacier, i was studying the high peaks, which had all been hidden in clouds the only other time i had been in the area.  Besides seeing some truly incredible calving off a hanging glacier high on the cliffs, i witnessed the cliffs themselves collapsing into a cloud of dust.

Nobody else seemed to notice, and at first i doubted myself, thinking maybe it was a just a suddenly appearing cloud. I couldn't hear anything but it was very high up and i was right next to the engines. On the way back the dust had lifted, and i could see a fresh pile of rubble at the base of a chute, along with fresh dusty rock on the cliffs above.

The rockslide created a cloud of dust that then lifted to reveal a pile of rubble at the base of a long rock chute.

For those who are interested in clicking this is a large, full rez crop of the rock pile (on the left) after the dust had lifted.

The peculiar thing about it was that far below, down at sea level, was a large waterfall disappearing into skree field. Sandor pointed it out to me, noting how strange it was for a  waterfall to disappear into a pile of rocks. It was peculiar to me to, not so much that it existed as much as me having absolutely no memory of seeing it the year before. I recognized pretty much everything we had seen that day, but not this obviously unusual waterfall.

An otter relaxes on it's back while the mountains crumble around it.

A few months later i was comparing shots from the previous year and i came across a photo of the very waterfall that i couldn't recall seeing. During 2010 it had been a very different place. In the time since there had been a massive rockslide, ripping the alders off the cliffs and burying a portion of the forest below under tons of rock. Whether it had happened in the middle of winter or just a few weeks prior i have no idea. What was clear was that the mountain, still busy breaking apart, was a very dangerous place to hang out. As exciting as it was to see something change so significantly, it was at the same time deeply troubling when i realized how much time i've spent in pretty much the same types of area.

The waterfall in 2010 cascaded along the boulders all the way down to the forest.

This is what it looked like in 2011. That's a dramatic difference. The water disappears into the rocks and the slope of Alders has vanished.

Above is a direct comparison of the two years. They were taken at different angles but i have scaled and matched them vertically. You can see that most of the vegetation has been wiped off the cliffs, and a large amount of debris has blackened the Baker Glacier. The rockslide i witnessed was off of the highest cliffs. If the original event started up there, the rockslide would have traveled at least 6,000 vertical feet, probably more. Also of note is the rubble at the bottom of the falls. It looks like the rubble must be thick enough to eat up about half the height of the falls last cascade.

A boat speeds off towards massive Mt. Gilbert, more than a 9,500 ft. climb from the water.

The rest of our cruise that day was ideal. The weather was perfect, there was a generous supply of wildlife, no ice choking the fjords, and the warmth had the glaciers putting on a crowd pleasing show of destruction.

 Our cruise paused for about 10 minutes to watch a wale. 

 

One day i'm going to get a good picture of a Dall Porpoise. Seems like they come by every time i'm out on a boat, but damn, they are soooo fast and unpredictable. Much harder than whales, which aren't easy either. The first picture i was aiming for the middle but i was so slow i ended up getting the guy in the background. By the time you see them coming out of the water they're almost gone again. 1/500th is the minimum shutter speed that i'd recommend.

Being a baby mountain goat is a hard life. This pair was climbing up the cliffs of the fjord enabling the boat to get very close. The goats started low but had gotten very high by the time we backed off. I have to say i was relieved to leave them alone. I could see that the mother was getting stressed from the proximity of the strange boat full of onlookers. On a couple of instances she seemed to have some judgement problems. I didn't want to see a mistake.

 The Tebenkof Glacier fills the valley immediately adjacent to Blackstone Bay and looks inviting. Contrary to it's appearance it sits back well over a mile from the shore. One interesting way to get there might be from Surprise Cove just to the east (left) where there is an actual campground and trails of some sort.

Harvard Glacier more than 20 miles distant.

I always like it when the white ice is sticking up above the green foliage.

It looks like water but it's all ice. Most of the time glaciers crumble away in a million pieces like this, as opposed to calving off huge blocks and pillars.

As usual the final stop was at the Rookery across from Whittier.

The Island Princess shrinks away

I order not to repeat myself i have withheld many images of the actual glaciers on the cruise. To see more, and also see Prince William Sound in a different mood check out my post from last year on the same cruise.