Tagish Lake Meteorite

By latest report, Dee and Cal are not going to Whitehorse, but were to spend the night last night in the town of Tagish, which gives me the chance to write a little about the Tagish Lake Meteorite.

"On the morning of January 18, 2000, a 150-ton space rock plunged into the earth's atmosphere, landing between the Yukon Territory and British Columbia in a remote vacation village, Tagish. The rare Tagish Lake fireball left an orange-white and blue contrail that lingered for 10 to 15 minutes as hundreds of observers witnessed the early morning events.

"The first aerial over-flights showed no crater or fragments left to demark the fireball or its impact. But fortunately for the science community, one week later on January 25th, a nearby resident, Jim Brook, found the first meteorite fragments while driving homewards on the ice of Taku Arm in Tagish Lake. He knew the frozen lake well, and had the presence to pick up the dark icy rocks with his hand inside a plastic bag. What Brook had uncovered was an extraterrestrial clue from the early solar system, a 4.5-billion-year-old meteorite.

"To date, 500 more fragments have been found near Tagish Lake and hundreds have been recovered from the site - many still encased in ice. The space events of January 18th were the largest ever recorded over land by the Defense Department satellite systems. Scientifically, ;[Tagish Lake] is the find of a lifetime,' says Peter Brown, meteor scientist in the Department of Physics and Astronomy at The University of Western Ontario and co-leader of the meteorite recovery investigation. 'The entire process of recovery of the material and determination of where it comes from makes this the scientific equivalent of an actual sample-return space mission - at a thousandth of the cost.' " (From AstroBiology Magazine.)

The Rocky Mountain Trench

On the High Plains and into the Canadian prairie, the Terrain View of the map has, with notable exceptions, been mostly monotonous. Not so now. I have been watching the terrain ahead as Dee and Cal approach the Northern Rockies, and for a few days now I have noticed a feature that seems highly unusual, a deep valley in a perfectly straight line for hundreds of miles, the orientation of which is an almost uniform 150/330 degree geographic north vector. Today I discovered that this is the Rocky Mountain Trench, primarily the result of faulting (with minimal glacial carving). What you see in the image above is the northern half of the Trench, beginning at the Yukon/B.C. border. It continues at just a slightly different angle to the southeast all the way to Montana.

For orientation, Fort Nelson is in middle of the upper right quadrant (at the confluence of three rivers). The town of Watson Lake would be at the top edge (or barely above it) and toward the left. Prince George would be just off the bottom edge and toward the right. The large lake in the middle of the Trench is Lake Williston on the Peace River. To the northwest, the Tintina Trench continues on through the Yukon to Alaska.

The mountains east of the Trench are the Rocky Mountains, but to the west of it are the Cassiar Mountains in the north and the Omineca Mountains a little further south. We will check out the Trench again when the trikers come back through it a little further south on their way home.

Lac St. Anne Pilgrimage

Dee and Cal are camping at the shores of Lac St. Anne tonight, the site of the largest annual spiritual gathering of Native people in Canada.

"A long-established annual meeting place for Aboriginal peoples, this lake became a Catholic pilgrimage site in the late 19th century. Since 1889, First Nations and Métis people have traveled here in late July to celebrate the Feast of Saint Anne. This saint, widely revered as the mother of the Virgin Mary and the grandmother of Jesus, embodies the grandmother figure honoured in many Canadian Aboriginal societies. Lac Ste. Anne is an important place of spiritual, cultural and social rejuvenation, central aspects of traditional summer gatherings for indigenous peoples."

Between 30,000 and 40,000 people are expected to attend this year (July 18-23).

Quiz: Longest Rivers and more

Quick, name the longest river in the United States. If you said the Mississippi River, you are close. Acording to the U.S. Geological Survey, the Mississippi is the second longest river (2340 mi), followed by the Yukon (1980 mi), Rio Grande (1900 mi), St. Lawrence (1900 mi), Arkansas (1469 mi), and Colorado (1450 mi). First place, however, belongs to the Missouri River, at 2540 miles in length.

Next, name the three largest man-made lakes in the country. If you got the first two, Lake Mead and Lake Powell, both on the Colorado, I am impressed. If you knew the third, Lake Sakakawea on the Missouri River, I am very impressed. Yesterday Dee and Cal crossed the Missouri River at the upper end of Lake Sakakawea.

Now name the explorers who followed this river into the Pacific Northwest from 1803 to 1806? This question is a bit easier, but I will let you follow the link to confirm their names. On Christmas Eve of 1804 they finished building Fort Manden on the river at what is now the other end of Sakakawea Lake.

Finally, can you name the longest undammed river in the contiguous U.S.? This would be the Yellowstone River, which flows into the Missouri ten or fifteen miles upstream from where Dee and Cal crossed it. The explorers I'm talking about followed both rivers because they appeared to be about the same size.

The river crossing by satellite. Williston is at the top and the lake is to the right.