Dave B wrote:Basic winter travel requires skills in:
1. Snow travel (including self arrest and some crampon technique)
2. Avalanche awareness
3. Proper gear and use (including emergency bivy)
5. Rational decision making
If you intend to only climb in CO you can skip the crevasse stuff, if you plan on climbing glaciated peaks then still hone the rest of your skills and then work on glacier skills.
We took CMS's avi 1 class with Eli Helmuth, terrific class, great instructor and guide. I really liked the weekend class as you got plenty of time to work on skills in the field, I really feel that practicing what you learn in class/text while under the tutelage of an expert is the best way to learn and given the risk factor in the Rockies you really need to know this stuff if you're heading out in the winter.
The snow skills you really need to practice as well. Spend a good bit of time practicing arresting a fall, do it forward, backward, head first, feet first, weak side, strong side, and practice a lot. You want to have this stuff down so you go into arrest position immediately, if you can't you might as well leave the axe behind as you're just as likely to hurt yourself with it. Practice snow anchors and belaying on snow as well, if you get into a situation that requires these skills you need to know how much you can trust a snow anchor and how to effectively employ a dynamic belay. Twenty years ago I took an American Alpine Institute week long mountaineering class on Mt. Baker and you cover all this stuff plus the glacier, crevasse and rope skills, again, no better way to learn it than to practice and employ it the environment you'll need the skills in. It's not the cheapest way to learn but you develop a lot of skills quickly. As somebody mentioned you can practice the rope skills required for crevasse rescue but there's nothing like doing a one-on-one arrest and crevasse rescue where your partner actually jumps into the crevasse and you're required to stop the fall and extract your partner (done under belay). I sure wouldn't want to experience it for the first time under an actual fall, you want it down-pat before you really need to perform in an actual fall. If you want the glacier skills you're much better off getting those on a real glacier and that ain't happening in CO.
Review and practice the other items Dave B listed and don't under estimate the gear, navigation, and good decision making, there is a big difference in walking up a well established trail in summer and navigating a safe route in winter.