I'm a college basketball player and have dealt with this problem since I was 14 years old. I've seen numerous doctors, team trainers, etc. to try and permanently fix the problem but over the years I've learned how to keep the pain manageable. The number one biggest pain reliever for jumpers knee is rest. I always find that if I end up taking a week off from jumping that after my return my knee feels rejuvenated (until about a week later of hard practicing, then it hurts again haha). Secondary to resting it are antiinflamatories. Taking 800mg of ibuprofen when you wake up and another 800 at some point in the afternoon will make your day of riding way better. Like the above guy said also, stretching is really helpful. Do that stretch where you grab your foot and pull it up toward your butt as hard as you can and hold it for at least 15 seconds. Do this for 3 sets. The same applies to the hamstring stretch (grabbing your toes while sitting). Lastly, make sure you warm up your knees before you go out and hit the slopes. That means doing some body weight squats (heels staying on the ground, getting as low as you can) and some weighted leg extensions (have a friend hold your leg while you push to extend it while sitting). If you go out without warming up and hit a jump right away or try to ollie, there's a good chance you're going to have some microtears which will ruin the rest of your day.
edit: yes and ice it too after you're done riding. shouldn't be too much of a problem to find some ice right?