As much as every combat situation is similar to every other one it's also unique.
There are always situational variables the good commanders (be they officers leading a division or sergeants leading a squad) take into account. And as always, movies are NOT a good source of information.
You mention skis ... story time:
Back in 1976ish the Norwegian government decided it was time to relax their post WW II policy about foreign troops being permitted on Norwegian soil (don't know the details, it was just what we were told at the time). So, since the USMC was slated for Norway in the event of WW III they sent some up there for a joint exercise with the Norwegians. And FAR more importantly to test the currently stockpiled/issued cold weather gear (90% of it failed miserably, modern Marines may thank us for sleeping mats, an idea we stole from the Norwegians, and Gore-Tex cold weather gear). So we found ourselves near Tromsø in November ...
Of course everyone (in Norway at least) knows US Marines spend all their time in jungles (WW II and Vietnam) thus know absolutely nothing about snow. Needless to say the guys from Colorado, Utah, Montana, Minnesota, Alaska, Maine, and other states were skiing is fairly popular all strapped a pair on and paid the Norwegian base camp a 4 AM visit. For some reason they didn't seem to expect us to do it to them at all, much less before they could do it to us
