In the search for remnants of a meteorite, a University of Calgary professor is seeking more video of the fireball that was visible across parts of Western Canada when it entered the Earth's atmosphere over the Labour Day long weekend.
The asteroid fragment is estimated to have weighed between one and five tonnes before it broke up, but surviving rocks have not yet been found.
Witnesses in B.C., Alberta, Saskatchewan, Montana and Washington reported seeing the fireball streak across the sky. It's thought to have landed south of Kaslo, B.C.
U of C professor Alan Hildebrand is now looking to gather more video of the meteorite.
Researchers from the university have travelled to the Kootenay region of B.C. to interview eyewitnesses. They also hope to locate any video taken by security cameras in an effort to better pinpoint where these space rocks may have landed.
"Social media and the web are making it easier to gather information, but you still have to be in the field to collect and calibrate observations," said Hildebrand.
A dedicated fireball all-sky camera run by Rick Nowell at the College of the Rockies in Cranbrook captured a detailed record of the meteorite from start to finish, which will be used to calculate a pre-fall orbit.
"This is a great opportunity to recover meteorites that have fallen from a known orbit — which has been done only about two dozen times before and is a big science bonus," said Nowell.
Using additional clues from about a dozen other videos and eyewitness accounts, the researchers have pieced together an approximate trajectory.
The rock hit the atmosphere northeast of Priest Lake, Idaho, headed slightly west of due north. Racing across the border, it passed west of Creston, B.C., heading up the Kootenay Lake Valley to cross the Crawford Bay peninsula.
"The fireball ended southeast of Kaslo, B.C., after travelling across more than 100 kilometres in approximately eight seconds and penetrating deep into the atmosphere, shaking the Kootenay Valley with thunder-like booms," said Hildebrand. "The largest rocks may have fallen into Kootenay Lake.
"We now have a preliminary estimate of where meteorites fell on the east side of Kootenay Lake, stretching from the community of Riondel to Garland Bay," he said.
"Anyone interested in searching for meteorites should know that the area is mostly forested with moderate to steep slopes. Also be mindful the fire risk in the area remains high."
Researchers encourage anyone running security or wildlife cameras in the Kootenay Lake area to check their cameras (Sept. 4, fireball start time of approximately 11:11 p.m. MT, to see if they captured the light and shadows cast by the fireball).
Anyone with a video is asked to contact Alan Hildebrand at email@example.com. With enough video information, a precise trajectory can be calculated and a better prediction made of where the meteorite fell.