Ice Ice Baby!

Since I'm surrounded by them every day, no matter if I'm working on the boats or have a day off, let's talk glaciers. My title is a little misleading, since a glacier ISN'T just ice- compacted snow,,gas bubbles, eroded sediment, huge rocks, little pebbles...(thinking of Lauren who collected pebbles from glacial ice)

FIRST, some pictures. 

Aialik Glacier, which I went to my first day working on the boats. Haven't been back since! 

Northwestern Glacier, which I've been to 50-60 times. It never gets old!! 

So, what IS a glacier? It's a large, dense, compact accumulation of ice that is able to move under its own weight. As snow accumulates over the years, it gets compacted under its own weight, and develops into something called firn. Eventually, this firn compacts even further and becomes glacial ice. 

Both the Aialik and Northwestern Glaciers are tidewater glaciers, which means their terminus is in the ocean water (kinda self-explanatory!) These types of glaciers are obviously good for a boat tour :) 

One of the most frequently asked questions we get on the boat is, "why is the glacier blue?" Clearly, the ice in your freezer at home isn't blue (OR IS IT??) First of all, there's A LOT of very dense/compact ice there. Look at the small pieces floating inmthe fjord in the pic above- they look like normal ice, but the glacier is blue ish. The blue color results from the blue wavelengths of the visible light spectrum being reflected & transmitted out of the ice. The blue end of the spectrum is made up of short, active wavelengths that are not absorbed easily, whereas the reds/oranges are absorbed quickly. The deep cracks in the ice are even bluer, because the light bounces around even more. 

A top portion of the NW Glacier, showing BLUE color!! 

A cool phenomenon we've only seen a few times this summer is called an ice fall. It occurs when small pieces of ice fall down, and eventually encounter a chute that they slide down and pour off the glacier, looking like a waterfall. In the pic above, the chute (which has been there pretty much all summer) is between the two rock exposures in the middle of the glacier. It's whiter than the rest of the glacier, since there's been a lot of little ice falls, and like I mentioned earlier, little pieces don't look so blue.  We saw a 2-3 minute ice fall the other day (8/17)- check it out below.

The beginning- see how the little pieces of ice & snow look like water going over a waterfall? 

When it first hit the water!

Still going...

And some black & whites of the fall as it started to slow down...

 

Ice falls are pretty spectacular- not something that we get to see every day, although I'm sure they occur in the other 23 hours a day that we're not at the glacier :) 

The snow in this rock exposure reminds me of Gizmo from "The Gremlins" Do you see it??

Bear Glacier, which we pass by every day on our way out to explore. 

Some harbor seals hauled out on large ice floes in Northwestern Fjord. 

Dense ice cover in the fjord. All of this ice had calved off of the glacier, and will be melted in the next 24 hours or so. This means that the ice we see floating in the fjord one day probably isn't the same ice we see the next day.