The Missoulian, September 27, 2009

The story I find most interesting this week continues to be the local wildfires, particularly the Kootenai Creek wildfire.  The Missoulian had two updates today, here and here.  I had been on a field trip yesterday; when returning along I-90 smoke from the Kootenai Creek fire was obvious in the Bitterroot Valley to the south:

Smoke from the Kootenai Creek fire.  View from I-90 E.  Downtown Missoula is just barely visible above the trees on the left side of the photo.  Stevensville, the town nearest the fire, is a little more than 30 miles from this vantage point.

When I got home I decided to go out and take a few pictures.  I traveled south on Route 93, which follows the Bitterroot Valley.

The view from Lolo, just south of Missoula.

As I got closer to Stevensville, the clear, blue sky was no longer visible.  What appears to be a cloudy or overcast sky is entirely smoke.  The plume of smoke continued from here across the valley to the east.  The mountains on the east side of the valley were either extremely hazy or entirely invisible.

I drove only a couple miles or so beyond this sign.  It was late, I was tired, and I didn't think I needed to see too much more.

I pulled off Route 93 to take this photo (below), and then I headed home.  Again, this fire was sparked by lightning in early July.  I can't imagine being one of the residents dealing with this.  When I stepped out of my car, it smelled like the biggest campfire ever.  Their hair and clothing, their homes, their cars - everything must be invaded by the burning smell.

The horses didn't seem to mind.  This photo was taken just south of Florence, about 3.5 miles north of Stevensville.

Pre-evacuation orders have been given, and some livestock have been moved, but there is no mandatory evacuation now.  As you'll see from the links above, firefighters are optimistic for the cooling weather and a shift in wind direction.

Field Trip to Glacial Lake Missoula

Last weekend (September 12) I enjoyed the first of many weekend geology field trips scheduled for the fall semester.  This field trip was part of the Winston-Thompson symposium, honoring UM Department of Geosciences professors emeriti Don Winston and Gray Thompson.

So, those of you in the know (um...GeoGuppy?) will wonder if I've taken possession of a time machine, as Glacial Lake Missoula no longer exists.  Much like the former Glacial Lake Hitchcock in the Connecticut River Valley or Glacial Lake Cape Cod in Cape Cod Bay, Glacial Lake Missoula was created during the Pleistocene period when the advancing Purcell Lobe of the Cordilleran ice sheet dammed the Clark Fork River (which runs through Missoula) near Pend Oreille, Idaho. The impounded river, as well as some of the melting ice, filled the valleys from Hamilton to Polson.  At its greatest extent, GLM had a depth of 600 meters and occupied a volume of 500 cubic miles!

http://vulcan.wr.usgs.gov/Volcanoes/ColumbiaPlateau/summary_columbia_plateau.html

Of course, most of you are probably more familiar with GLM as its waters were the source for the floods that created the channeled scablands of Washington and Oregon.  See Nova's "Mystery of the Megaflood."  Of the many scientific controversies surrounding GLM, the number of "megafloods" produced is probably the greatest.  It is thought that the lake filled and then catastrophically drained multiple times.

So, our field trip was to visit the many landforms and deposits found in the area once occupied by GLM.  Sadly, we are too many hours away from the scablands to have visited those - a different trip, perhaps.  We also did not visit the mega-ripples created as waters catastrophically drained westward, but I understand that they are more spectacular in aerial photographs and maps than from the ground.

What we did visit: diamictite deposits (clay, silt, and gravel) interpreted as glacial till due to the presence of striated boulders, overlain by paleosol (ancient soil), then silts with climbing ripples and layers with syn-sedimentary deformation, and finally laminated layers (interpreted) as varves, with dropstones.  Was that a sentence that made you go, "hmmm....?"  What we saw: the gravelly deposits of an advancing glacier, followed by soils, and then by thin layers of sediment that were deposited in a deep, quiet lake.  Those layers have "dropstones," literally pebbles and cobbles that dropped through the water from icebergs floating in the lake.  We also visited an area of the lower Flathead River thought to be where floodwaters burst through a canyon, depositing rock debris.

Photos: Top, left: The group at an "outcrop" of unconsolidated sediment north of Arlee, Montana.

Top, right: Diamictite overlain by fine sediments; note soft-sediment deformation at elbow level; also climbing ripples; grading up into varves.  Bottom: Striated boulder in diamictite allows for interpretation of glacial till.

The weather was lovely (80+ degrees, clear, blue skies) and there were dozens of happy geologists to share it with.  The field trip was followed by a barbecue at Professor Winston's legendary home along the Jocko River.  As I have summarized for those of you on facebook, we enjoyed: beer, bison burgers, a bonfire, and banjo music.  It was great company, a beautiful, warm night, and good music (the banjoist was accompanied by guitars, bongos, flute, and cello!).

Photos: Left: The Lower Flathead River as it flows away from the Kerr Dam, south of Flathead Lake.

Middle: Dropstones in varves.  Right: Geologic hoe-down around a campfire.

The next field trip: A geomorphology class data collection trip to the Mattie V Creek.

Sunday Missoulian - September 20, 2009

The Missoulian is the primary local newspaper (although I dare say it is smaller than the Cape Cod Times).  I've been reading it every Sunday to get a better feel for my new community.  I've found that land resources issues are very important in Montana - timber production, grizzly habitat, open space, and big game hunting (wolf season is now open in Idaho and parts of Montana).  My favorite section of the Sunday Paper, "Territory," focuses on life in Montana.  In any case, I thought I would share an occasional story from paper to give you a better sense of the area too.

• "Recruiting on the Rez," Chelsi Moy, September 20, 2009.  There is a lot of concern for American Indian students at UM, as they often have difficulty acclimating, and have lower retention and graduation rates.
• The Kootenai Creek wildfire, Betsy Cohen, September 2009.  It is no wonder the sky turned a dark, cloudy brown when a cold front moved through Missoula yesterday.  Stevensville is just 30 miles southwest of Missoula.  I may be studying rocks from the Bass Creek area (after the fires are out).