Edmonton fireball story

October 18, 2019

By professor Chris Herd, University of Alberta in Edmonton, Canada

It had been an unusually wet summer in central Alberta, so when the Labour Day long weekend came along and the weather finally looked decent, people made the most of it. My family and I borrowed a tent trailer from a friend and went camping at the Cold Lake Provincial Park Campground. While packing up on Sunday morning, I got a text from a meteorite hunter colleague that simply said “Hi Chris, I may be ready to hunt this meteor.” A quick check of social media told me that many people in the area had seen a fireball at about 10:23 pm local time the previous evening (August 31; 04:23 UT September 1); #yegmeteor and #yegmeteorsighting were trending (YEG is the Edmonton airport code). Not only that, but a remarkable number of personal home security and doorbell cameras had picked up the event. A little while later I received another text from our Faculty of Science communications director asking if I could do an interview with the Edmonton Journal, which I arranged to do that by cell that afternoon from outside a cafe in the town of Cold Lake. While I knew very little at the time, I could at least provide commentary on what the difference is between a meteoroid, fireball and a meteorite, and to say that we would check our cameras to see if they picked up the event!

The next few days were a blur of activity, including radio and TV interviews, and a flurry of emails with Hadrien Devillepoix and Martin Cupak from the GFO. The American Meteor Society (AMS) had a trajectory that ended near a small town called New Sarepta, about an hour’s drive southeast of Edmonton; however, that was based on non-calibrated eyewitness observations. Within the GFO network, it turned out that our cameras to the west of the fireball were not working well; a camera that we would later realize was almost directly under the fireball had had its power cut by a circuit breaker only 10 days prior. However, our camera at Lakeland College in Vermilion (Eastern Alberta) recorded the entire thing! Observations for triangulation were obtained from photographers that were out capturing the Northern Lights, which happened to be especially active; one particularly striking image from Shane Turgeon shows the start of the fireball against the background of stars and aurorae. Hadrien used this and other images, and by Thursday September 5th we had a trajectory and a potential fall zone, the latter generated by Hadrien, Martin and others from a dark flight model that incorporated weather modelling and atmospheric sounding info obtained from contacts at Environment Canada.

The fireball turned out to be east of the AMS projection, with the end point 20 km altitude above the town of Camrose (pop. ~19,000), with the fall zone in agricultural land to the southwest of town. With the help of my postdoc, students, and meteorite hunting volunteers we scoured the roadsides in the area over the following days, and I secured permission to search on several farmers’ properties. We also took advantage of the availability of a DJI Matrice 100 mapping drone from my department, which we deployed over two fields (one of wheat of one of peas) to map out and attempt to detect any damage that might have resulted from a meteorite or meteorites. In spite of all this, no meteorites have been found - but the projected mass (perhaps as small as only 1 kg) coupled with the land use suggests that any meteorites are hiding within fields which still have crops on them. Further publicity was carried out after this to provide an update to the public, which generated a big response. At that time - and continuing to the time of this writing - we are waiting for the farmers to harvest their crops so that we can do a search of the fields, both systematic (along the fall path), and targeted (based on drone results). Hopefully this happens before the snow flies - stay tuned!

Here is the official press release on the meteorite hunt at University of Alberta web site.