Ideally you would spend the summer lifting heavy and running slow, transitioning into plyometrics and interval training in the fall.
Its almost November now though, so what you really need is a crash course program to make you less sore on the first days.
For the crash course you want to focus on plyometrics.
here is a good program from backcountry.com:
“
Mini Leg Blaster
10x Air Squats
5x In-Place Lunges (5x each leg, 10x total)
5x Jumping Lunges (5x each leg, 10x total)
5x Jump Squats
Full Leg Blaster
20x Air Squats
10x In-Place Lunges (10x each leg, 20x total)
10x Jumping Lunges (10x each leg, 20x total)
10x Jump Squats
Work up to 5x Full Leg Blasters, with 30 seconds rest between each effort for your dry land ski training. Be careful. Leg Blasters train eccentric leg strength and can make you terribly sore, so don’t start at the end.
Instead, perform Leg Blasters 3x/week, with at least a day’s rest between training sessions, for the 4 weeks before the season starts. This means 12 total training sessions.
Here’s the progression:
Sessions 1-2
10x Mini Leg Blasters, 30 seconds rest between efforts
Sessions 3-4
2x Full Leg Blasters, then 6x Mini Leg Blasters, 30 seconds rest between efforts
Sessions 5-7
3x Full Leg Blasters, 4x Mini Leg Blasters, 30 seconds between efforts
Sessions 8-10
4x Full Leg Blasters, 2x Mini Leg Blasters, 30 seconds rest between efforts
Sessions 11-12
5x Full Leg Blasters, 30 seconds rest between efforts“
https://www.backcountry.com/explore/train-eccentric-leg-strength-for-alpine-skiing
if nothing else just do bunch of jump squats and jump lunges.