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Glacier Discovery Blackstone Bay Cruise Page 2

Alaska Railroad Glacier Discovery Train

and Prince William Sound Blackstone Bay Glacier Cruise

June 24, 2005
Copyright 2005 by Richard Elgenson



Our first surprise destination was a hidden waterfall.  Captain Crabough put the bow of Emerald Sea within 100 feet of this magnificent feature.  The engines were cut and we drifted in place for about 10 minutes while all passengers were encouraged to make their way to the bow and take pictures.  This waterfall appeared to be fresh water only without glacial silt.


Continuing our journey to the Blackstone complex, we passed several "rafts" of otters.  Captain Crabough gave more narration regarding the otters, who are called the "old man of the sea" due to their white faces.  Otters bodies contain no blubber, so their beautiful coats keep them warm.  The Exxon Valdez oil spill ruined the local otters waterproofing.


Next we passed by Willard Island, known for camping and kyaking adventures.  Other local tour companies offer this type of trip from this beautiful spot.  Blackstone Bay features 8 glaciers, 6 on the sides of the bay and 2 tidewater glaciers at the head end separated by a point of land.


We visted Blackstone Glacier first and Beloit Glacier second.  Other glaciers in the Blackstone compex include Ribbon, Lawrence, Marquette, Concordia, Ripon, Burns and others.  Early in the cruise, Captain Crabough announced that passengers were welcome to visit the bridge after lunch.  As I was in the well equiped bridge, the Emerald Sea was about to pass over the Blackstone terminal moraine.  Having spent many a weekend in the Sierra Nevada mountains in California before discovering and falling in love with Alaska, I learned a few facts about glaciation.

As a glacier moves down its valley, it scrapes and scours valley sides and bottoms.  As it reaches its terminus, it deposits this material.  In the mountains, a terminal moraine looks like a pile of rocks, usually at the mouth of a valley.  In Prince William Sound, the ocean covers the terminal moraine, sometimes by only 10's of feet of water.  It always amazes me to watch the depth sounder while creeping over an underwater terminal moraine.  The tides always must be factored in in such a cruise.  The depth sounder screen moves from nearly hundreds of feet in depth to a spike and then goes back down to deeper bay bottom. Considering the June 24th 2005 tide at Blackstone Bay, the terminal moraine was only 18 feet below the water surface.  It helps that the Emerald Sea has a shallow draft.  While there was a major period of glaciation about 10,000 years ago, there have been minor ice ages as well.  Around the time of Columbus, glacier ice covered much of the land above the 60th parallel of latitude.  The Prince William Sound area was likely iced over in the last minor ice age.


On our way to Blackstone Glacier, Captain Crabough stopped the Emerald Sea and the crew brought some glacial ice onboard.  There are a number of names for glacial ice in the ocean or lake water.  An "iceberg" on a piece of ice which rises 15 feet or more above the water surface.  Other names include brash ice with 0 to 3 feet of ice exposed, growler ice with 3 to 7 feet of ice exposed and bergy bits with 7 to 15 feet of ice exposed.  Careful observers may notice locations where silty fresh water seems to stay separate from salty ocean water.  The ocean water looks cloudy because the fresh silty water has a different specific gravity than ocean saltwater.  Captain Crabough mentioned that many ocean locations in Alaska stay ice free in wintertime due to the warm Japan current flowing nearby.  Next, we were educated about the different kinds of glaciers. Blacktsone and Beloit are fjord or tidewater glaciers due to the ice terminus being below sea level and feature almost vertical faces of ice.  Valley glaciers such as Billings glacier terminate in a valley above sea level.  Hanging glaciers terminate above valleys.  When you take the Alaska Railroad Glacier Discovery train to Grandview, Deadman glacier is visible and pointed out on the nature walk.



We arrived at Blackstone Glacier and Captain Crabough silenced the engines once again and we waited for something to happen.  Nothing happened and Captain Crabough recited the ways to cause a glacier to calve off some ice.  One way is for everyone to put their cameras down.  Next is to blow the horn which the Forest Service frowns upon.  Next, the boat must leave the glacier and surely the glacier will calve ice when nobody is watching.  Captain Crabough entertained questions from the passengers and I asked if anyone has ever dropped their cell phone off the Emerald Sea.  He replied no, but only since there is no cell phone service at Blackstone Bay.  In the past, one passenger dropped her digital camera, which then found its way through a drain opening off the deck and into the bay.   I have a few items on the bottom of Long Beach Harbor from my sailboat.

Page 3 Blackstone Bay Glacier Cruise