From what I see on the video, the rear axle locked up, what very likely is result of lack of practice in snow driving and pushing the brakes too hard, what made transmission downshift and holding the drive wheels.
Proper practice in this situation would be using trailer brake controller in pulses.
Growing up in 4-seasons I spend countless hours practicing ice and snow driving. That still pays 40 years later as practiced reactions stays with you, like bicycle driving.
When you have a job to come back to and kids who have to back to school, you are pressured to put yourself in less than ideal situations.
Took me retirement when going on vacations in June, I was advising neighbor taking care about my garden that my return date might be in September or November.
