2017-11-12 : Crawford Bay Meteorite – by Rick Nowell

Dr. Alan Hildebrand (a meteorite expert at the University of Calgary) has released photos of some small Crawford Bay meteorite fragments on CBC.  His grad student, Fabio found them.  It was a stony chondrite.  There are lots more pieces to find.  Alan says:

Finding rocks about the size of a loonie across a 20-kilometre stretch of forest is no easy task.  But this case was different because of the video footage.  “We know what orbit it fell from… and that’s only been done a couple dozen times,” Hildebrand said.  “So we now know what orbit this rock was on and that, of course, tells us a little bit about the structure of our solar system.”

Thousands of fragments, ranging from the size of a peppercorn to a bowling ball, will have hit the ground – but Hildebrand says most will be in the forest that blankets the eastern shore of Kootenay Lake.  He expects people will be finding fragments in the area for several years.

READ MORE Dr Hildebrand’s news release.

Where approximately to look?

Triangulating with these videos now locates the fireball trajectory in the sky with ~200 m uncertainty along a path 120 km long, recording its deceleration from 16 to 4 km/s.  Once the rock has slowed to <4 km/s it no longer produces light entering what is called “dark flight”.  Dr. Elizabeth Silber of Brown University calculated the surviving rocks’ paths as they fell to Earth pushed by atmospheric winds.

The predicted meteorite fall zone – what researchers call a strewn field – is  ~20 km long starting east of Crawford Bay and trending NNW across Bluebell Mountain to the Kootenay Lake shore north of Riondel.  The largest meteorites will be in the north.

Where are the meteorites?

With the prediction of where meteorites would have fallen, the U of C team headed into the search area and found the first meteorite on Oct. 29 on private fields in northeastern Crawford Bay.  Fabio Ciceri, a visiting M.Sc. student from the University of Milan made the first meteorite discovery.  Fabio says “At first I couldn’t believe it – ever since I was a child I got up with my father to see the night sky, and it was like a dream to hold a space rock in my hand.

A meteorite chunk was found by Fabio Ciceri, a masters student from the University of Milan who is studying at the University of Calgary. (Colin Hall/CBC)

The U of C team kept searching, but the approaching winter has made finding meteorites more challenging.

Dr. Hildebrand says, “We need to recover more and larger meteorites to learn what we can from this fall.  For example, with enough pieces we can tell how big the rock was when it entered the atmosphere.

Thousands of meteorites will have fallen ranging from the size of a peppercorn up to rocks weighing 5 to 10 kgs, but most will be in the forest that blankets the eastern lake shore.  To understand the challenge Hildebrand recommends standing on the main street of Crawford Bay looking north to the southern end of Bluebell Mountain, “More than one hundred meteorites are on that slope, all you have to do is find them.”.  And he expects that interested people will be finding meteorites in the forest across the strewnfield for years.

The U of C researchers also are still encouraging anyone running security or wildlife cameras in the Riondel area to check their cameras (Sept. 4 fireball start time of ~22:11:25 PDT) to see if they captured the light and shadows cast by the fireball.  This will help them check the fireball’s end location so more accurate fall locations can be predicted for the largest pieces.


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