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Our wilderness guide, Mister Kimery, told stories as we hiked through the sheltering trees.

"Lots of bears!" he said, pointing out a patch of blackberries, a favorite bear snack. Black (grizzly) bears and brown bears live throughout the mountains and forests of southeastern Alaska.

Mister Kimery taught us what to do if a bear approached: talk to the bear in a firm voice and slowly walk away. Real bears can be very unpredictable!

Soon, we peeped through the trees to see the lake--and beyond it, Davidson Glacier! "You're lucky it's a cloudy day," explained Mister Kimery. "Glaciers are most colorful under cloudy skies!"

Ahead, Davidson Glacier sparkled with deep blue and green lights. When we stopped for a rest break, I asked, "Why is the glacier blue? I thought it was made of ice!"

Mister Kimery took advantage of the break to explain more about glaciers. Glaciers begin to form when snow falls, but does not completely melt during the summer.

As more snow piles up, winter after winter, the weight of the snow presses down hard on the accumulated snowflakes. Air is forced out, and snowflakes begin to change. They turn into a special kind of ice, called firn.

With a grainy texture similar to sugar, firn crystals permit the glacier to move and flow. When it is big enough, the glacier begins to move down the mountain, drawn by the force of gravity, and by the power of melting and refreezing ice.

As it moves, a glacier reshapes the earth in many ways. Glaciers are powerful enough to crush and scrub away solid rock, or carry large boulders for long distances.

As they travel, glaciers pick up crushed stone and rock. When they stop growing, they release the rock as they melt, as a pile of gravel and small stones. This is called a terminal moraine: a deposit of rock and gravel dropped by a retreating glacier.

"But what about the pretty blue color?" I asked.

"Perry, when light strikes the special ice of a glacier, the ice absorbs the yellow, red and orange colors in the light, beaming back only the blue and green ones. That's why the glacier has a blue-green glow: from reflecting only part of the light waves that strike it." answered Mister Kimery.

"Time to get going!" he called. "We're nearly to the shores of the lake!"

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