THAT TIME FORGOT
Unearthing the many secrets of Glacial Lake Missoula
By PATIA STEPHENS
Sometimes science is spooky. Take, for example, the study of geology. Step out of your daily routine — the hum-drum world of alarm clocks, dirty dishes and must-see TV — into the realm of billion-year-old sedimentary rocks, lava flows erupting from vents in the earth and 30-mile wide chunks of ice damming rivers. It’s enough to freak a person out a little.
In Missoula, a glimpse of ancient shoreline on a mountainside is all it takes to yank us out of, say, a traffic-induced coma into the sudden sensation of being at the bottom of a 1,000-foot deep lake. Glub, glub. It makes you realize how insignificant you and your problems are, and how terribly fascinating this planet is.
Though it has been gone for about 12,000 years, Glacial Lake Missoula is never far from mind at UM, which sits on the ancient lakebed. Our mountains bear its scars: horizontal lines where waves once lapped; vertical crevices where soggy mud collapsed when its watery support was suddenly withdrawn; bare rock and talus slopes where fast-moving water stripped topsoil. Spoony Rock in the middle of the campus Oval is one of dozens of boulders scattered throughout the otherwise flat University neighborhood.
Scientific inquiry into Glacial Lake Missoula and its floods has only revealed the tip of the iceberg, so to speak. The subject remains an extraordinary enigma. However, recent scholarly efforts at UM have produced some interesting material on Glacial Lake Missoula, including a book, a children’s video, an economic analysis and at least one master’s thesis.
Forging a trail of discovery
Congressional approval of the geologic trail would stimulate local economies and, perhaps most importantly, further scientific research into this fascinating story.
"Modern science knows little about Lake Missoula and the channeled scablands [in eastern Washington]," writes UM environmental studies student Daniel Berger in his 2002 master’s thesis, titled "Ice, Water, Land, and Time: A Partial Story of Glacial Lake Missoula and the Missoula Floods."
"As far as I can tell," Berger continues, "the vast majority of geologists who have looked into it feel certain that Lake Missoula existed and that the channeled scablands were formed by floods, many of which likely originated from the Purcell Trench area of Idaho. That’s it. The rest is up for grabs.
"Some geologists believe that Lake Missoula existed between 40 and 100 times. Many believe that the ice dams holding back Lake Missoula failed catastrophically at the end of each period of lake formation and that the following floods were responsible for carving the channeled scablands in eastern Washington. Some geologists believe that Lake Missoula existed once and went away slowly and that the channeled scablands were formed by other flood mechanisms larger than what Lake Missoula could have produced.
"The permutations of ideas surrounding these two giant phenomena and their relationship are endless, and none are widely accepted."
jökulhlaups and blowouts
story begins in the early 1900s, when Montanan Joseph T.
Pardee identified Glacial Lake Missoula, and University of
Chicago Professor J Harlen Bretz announced that the channeled
scablands had been formed by massive floodwaters. Though
both geologists knew of the other’s
work, it was decades before anyone connected the dots out loud.
"Pardee and Bretz were geniuses," says UM geology Professor Emeritus Dave Alt. "Then we mere mortals can come along and put details on it." Alt is author of "Glacial Lake Missoula and Its Humongous Floods," a guidebook to the lake and flood path. Alt’s floods expertise has earned him the nickname "Mr. Blowout" among colleagues, though he claims never to have heard it. He also, when contacted for this article, insists he has no idea what "outburst flooding" is, though it is a term commonly used in the scientific community to describe any sort of sudden flood event. Asked if he prefers the alternate term "jökulhlaup" (an Icelandic word pronounced "yo-kul-hloip"), Alt has a bit of an outburst himself.
"’Jökulhlaup’ is absurd. I don’t recognize it as a valid scientific term," he says. "A jökulhlaup specifically refers to a glacier melted by a volcano beneath it. Outburst floods happen for a variety of reasons. ... Outburst flood makes a lot more sense." Alt goes on to say he prefers the term "‘giant flash floods.’ ... At least then you’re communicating, not trying to bamboozle people."
Whatever you call them, outburst floods are a hot topic in this time of global warming, and Glacial Lake Missoula is a contender for the mother of all outbursts. Discovering the signature it left on the landscape has helped scientists recognize past and potential outburst floods around the world.
One such disaster-in-the-making is in the Peruvian Andes, where scientists are keeping a close eye on a glacier just above Lake Palcacocha and the city of Huaraz. According to an April NASA news release, "an ominous crack has developed in the glacier. Should the large glacier chunk break off and fall into the lake, the ensuing flood could [reach] Huaraz and its population of 60,000 in less than 15 minutes."
NASA is using Aster, an earth-observing instrument aboard its Terra satellite, to monitor the Peruvian glacier. Aster is a sister instrument to Modis, which was designed by researchers in UM’s College of Forestry and Conservation.
The case of the missing water
No one is sure where the rest of the water could have come from. Shelden says maybe it came from the Flathead Valley basin, which at the time was filled with ice. Or maybe it came from a volcano that erupted underneath the massive Cordilleran Ice Sheet that covered Canada, as some Canadian geologists believe.
Alt doesn’t think so. "That volcano is just a cute little thing," he says. "It’s not very fierce. It doesn’t erupt very often."
He does agree that the missing water could have come from the Flathead. Another possibility, he says, is "seiching," or wave action, created when Glacial Lake Missoula broke through its dam and splashed into the shallower Glacial Lake Columbia, which covered the Spokane region.
Another mystery concerns the 2,000-foot-tall ice dam that blocked the Clark Fork River near the Montana-Idaho border. How, exactly, did it fail? Was it floated out of its moorings when the lake reached critical mass? Did the water tunnel underneath it — or over it — creating a canyon through the ice? Did the dam fail partially or catastrophically? Or was it D, all of the above?
One more question: Were humans around to witness the giant lake and floods? No geological evidence has been found, but Alt and others expect it will turn up eventually.
Perhaps the next generation of UM students will solve these mysteries.
Captivating kids of all ages
"The Really, Really Big Floods" first aired on Montana PBS in September 2002. Host Wynne Renz, then a Hellgate High School senior, leads viewers through conversations with middle-school kids and geologists, experiments involving ice blocks and fire hoses, and graphic animations of how the Missoula Valley might have looked filled with water. The end result is a fun, witty romp of a geology lesson.
"This is the cool part about science," Renz tells viewers. "You find one answer, and it opens up a thousand new questions."
Getting down to business
Using statistics from similar facilities, such as the Lewis and Clark Interpretive Center in Great Falls, the report suggests that out-of-state visitors alone could contribute an average of more than $2 million to the economy each year. But while some people want to see Congress enact the National Geologic Trail for economic reasons, others simply want to share this incredible mystery with others, in the hopes of someday solving it.
As Dan Berger says when discussing failure of the ice dam: "God knows exactly how that happened; the rest of us are still trying to figure it out."