The consensus on r/aviation seems to be that it was caused by wind shear.<p>> This looks like wind shear to me. It was a stable approach and then it suddenly got slammed into the ground. That doesn't look like pilot-induced change in descent rate, it is too sudden for that. A sudden change in wind direction (shear) when that slow can absolutely cause a sudden loss of lift.<p>> We have had almost 2 feet of snow up here since Friday, and are experiencing wind gusts up to 65 mph. Has basically been a winter hurricane.<p>> This is a CRJ landing on Runway 23 at YYZ. It is an 11,000’ runway. Winds at the time where gusting from the NE likely north of 30 knots, so this was a cross wind landing. My bet is that it wasn’t the worst situation that any of the pilots had been in. Delta is a pretty good company. Guessing (as a GA pilot and talking to pilots of bigger birds than this —- I know a few). Likely wind shear or wake turbulence. The wake turbulence part would be a reach considering the cross wind component would have blown it away by the time of this landing.