Alaska
& beyond - continued
Rev. 08/07/01
Alaska
& beyond - continued
Misc. Stories That Don't Fit Anywhere Else
On Internet there is an annual article titled "The Darwin Awards" for those who eliminate themselves from the gene pool by doing something extremely stupid. An example, the guy checking how much gas was in the tank by lighting a match so he could see into the tank -- boom! He now no longer contributes genes to the gene poll. Yes, it is a rather macabre concept.
My father was a minister in Seward, Alaska from 1925 to 1928. In those days steam ships and railroads were the mainstay of transportation in Alaska.
He used to tell tales of problems with moose and the trains. Of every once in awhile an exceptionally large moose, during the mating season in the fall, after he'd successfully wooed an attractive female moose, would challenge a locomotive coming down the tracks, thinking it was after his cow. Sometimes this resulted in the derailment of the locomotive. More often it resulted in elimination of the moose.
I wonder, is that the reason there are fewer huge moose today -- did the the "big moose" gene get wiped out by moose jousting with locomotives?
Short Course - Glaciers 101 or maybe just Glaciers ½
I've seen more glaciers in the last month and a half than I've seen before in my whole life, and learned more about them than I ever knew before.
To begin, all glaciers behave exactly the same way.
They all begin with snow piling up year after year without completely melting, until the weight of the snow compresses that at the bottom to the point it turns into ice. This continues for years, centuries, eons. The weight squeezes the ice at the bottom out, over mountain passes, and down valleys. This movement is slow -- an inch per day is fast. The heavy weight of all this ice, moving down a valley, gouges out all dirt and rocks, right down to bedrock, and pushes this mound of rock and dirt, which continue to grow, ahead of it. This mound is the glacier's moraine.
Two things are happening to this long sheet of ice. First, the ice field at the top is pushing the glacier out . So up there the ice is compressed. At the other end, where the moraine is, gravity is pulling on the ice, trying to stretch it. Ice doesn't stretch very well, so it cracks, with the sound of an explosion. The ice is hundreds of feet thick and the cracks can be as deep as that -- huge deep crevasses. Those pieces of ice, right at the face of the glacier actually break free and fall off of the face, where they melt. This is called calving.
Now, if the amount of ice pushed out of the ice field is more than the amount being lost by calving, the glacier will advance down the valley. If the amount pushed out is less than the amount lost by calving, the glacier will retreat back up the valley. If they're the same it will remain in the same place. Regardless, there is always new ice being pushed out at the top, and there's always old ice falling off of the face -- always movement of ice in the glacier.
If a glacier retreats, it's big moraine will remain right where is was when the retreat started, as a terminal (fancy word for end) moraine.
Tidewater glaciers, those that go right down to the ocean, are much more dramatic, calving huge icebergs off their face, hundreds of feet high, with a sound like a canon, falling into the water with an enormous slash – now these are GLACIERS. But they behave the same as all glaciers.
They push their moraine of rocks and dirt, ahead of them the same as any glacier. But here, it serves an additional purpose -- the mass of dirt, rocks and sand insulates the face of the glacier from the relatively warm ocean water, keeping it away and keeping it from rapidly melting the ice at the face. The glacier keeps pushing the moraine ahead, down the fiord, maybe a thousand feet deep, for miles and miles.
If something occurs to slow the glacier, make it retreat slightly and come off its moraine, the full face is now exposed to the ocean water. It starts melting rapidly and calving much faster than normal. It begins what is called a "catastrophic retreat," back toward, even to it's bedrock foot on land, leaving its moraine right there as a terminal moraine. This retreat may only take a few years, but by glacier speed this is really sprinting.
Once back on land it may rebuild its moraine, and once again, start moving down the fiord..
That, very, very briefly is a glacier.
To really learn about it, check the Internet or go to the library. Glaciers are fascinating.
Moose Damage -- 7/15
