Sit-skier Rose finished third overall in the World Cup series but could only manage to place seventh as Switzerland's Christoph Kunz took gold.
"I feel pretty deflated to be honest," he said.
"However, I can go away feeling confident heading into of the super-G. I've never had a full run from top to bottom on this course and that made me a bit apprehensive, so I checked a bit and you can't afford to do that in this field.
"I'm looking forward to the next two races. I'm going to put the hammer down."
Rose's team-mate Russell Docker thought he had completed the course but was disqualified after missing a gate.
"It is six hours since I inspected the course and things have changed in that time," he said.
"I've been at the top for a few hours desperate to get on and start the race so it's a real shame I didn't finish after missing a gate.
"It's been a great building-block for the super-G."
It was good day for hosts Canada as Viviane Forrest won the visually impaired downhill and Lauren Woolstencroft claimed gold in the standing events. American Alana Nichols took the sitting title.
Germany's Gerd Schonfelder won the men's standing downhill while Spain's Jon Santacana Maiztegui claimed podium top spot in the visually impaired event.
Forest - who has three medals at these Games - only started para-alpine skiing only two years ago and becomes the first Canadian Paralympic athlete to win gold in both summer and winter events - after twice being part of the successful Canadian goalball team.