Of course, you don't need to give it up.
This guy didn't, he competes for the US as a cross country skier (far more energetic in my opinion than downhill)
http://content.time.com/time/video/play ... 57,00.html
You obviously have to be prepared as for any exercise. You will need your meter, some glucose in case of hypos and your insulin to bolus for lunch. (or if you have unexpected highs, this has never happened to me on the slopes)
The biggest problem is keeping the meter from getting too cold else it won't work and to be honest it can be fiddly to test on the slopes especially if it's in an exposed position (taking off gloves, inserting strip etc) I tend to keep mine either well wrapped in my daysac .I actually use a little bubble wrap bag and a scarf. If it's very cold , then I put it in an inside pocket but then there is the difficulty of getting it out.
I have had a couple of times when the meter hasn't worked through cold,(so I take some dextrose just in case). It seems to warm up and work quite quickly once you get inside.
I find that exercise always drops my levels, and the cold does so even more . If I've had to carry my skis any distance to the slopes, I'm often quite low before I even start skiing so I tend to eat something like a lowish GI cereal bar before starting.
I do exercise a fair bit anyway, if you don't it would be worth doing something before going skiing as then you'll have some idea about how your body copes with exercise (being fitter helps with skiing anyway).
This site is a good starting place to find out about exercise and insulin
http://www.excarbs.com/basic-facts/
This site has a lot more but is harder to navigate
http://www.runsweet.com/