Distinctly Montana Magazine

59 w w w. d i s t i n c t l y m o n t a n a . c o m 19,000 YEARS AGO... It is quiet too, here on the edge of Glacial Lake Missoula. We stand on the beach of the lake, which happens to lap at the side of Mount Sentinel. As we look out to the horizon, almost ev- erything is underwater except for a few small islands: the peaks of mountains. The water is a beautiful turquoise blue that resembles a tropical lagoon, the result of white rock flour mixing in with the water as the summer sun melts the glacier. The dust of stone pulverized as the glacier scrapes across bedrock has created the nutrient-rich conditions for large blooms of algae, adding splotches of unlikely color to the surface and giving the air a tangy, leafy smell. Somewhere to the east, there are strange animals - giant bears and bison, saber-tooth cats, black-winged birds larger than any eagle —living and dying alongside creatures we would recog- nize today. The gigantic body of water in front of us is relatively recent in geologic terms, created over a half a century or so when the Cor- dilleran Ice Sheet, a solid block of ice with boulders and rocks captured in it, slid far enough south to choke the mouth of the Clark Fork River at Lake Pend Oreille. There, an ice wall 4,000 feet tall and extending north to the Arctic Ocean has come to rest. Even out here, 180 miles away from Lake Pend Oreille, the water conducts some of the com- motion created by enormous chunks of the ice wall calving from the central mass to fall, crashing, into Glacial Lake Missoula. The flow of the Clark's Fork has backed up where it meets the glacier, pouring water into a basin that reaches from Missoula to Deer Lodge and beyond, filling some 2,973 square miles of land with over 500 cubic miles of ice-cold water. But the air around you is warm, and that far-off wall of ice is melting. As it melts, the water around the wall itself churns with the current of the river, and iceberg calves grind away at it in the flow. One day soon, the unfathomably high and seemingly im- penetrable ice dam will give way, spilling this huge glacial lake across Idaho, Washington, and Oregon with prehistoric ferocity. All that water will wash the earth of anything organic, taking the faces off mountains, spraying through narrows, shaping the land with its flow, and, ultimately, creating a wasteland. Glacial Lake Missoula will empty itself over three tumultuous days. It's hard to overstate the devastation it will bring. Then, it'll do it again and again as the Cordilleran Ice Sheet resettles, creating a new ice dam and refilling Glacial Lake Missoula, only for the in- evitable to happen again as few as 20 and as many as 100 times. But all of that latent destruction seems impossible from here on the shore of the lake. A body of water this large feels infinite and eternal as it slowly fills the mountains. A piece of ice the size of a house bobs among the peaks, work- ing its way south. As it rolls in the freezing water, its weight re- settling as the sun warms any surface exposed to the sun, the light catches and reflects in spiky glints. The gentle chuckling of the waves is the sound of a torrent building drip by drip. Mountains around Missoula still show the water levels of Glacial Lake Missoula

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