Jeepers, that's a bad day! With going through my first entire winter here, it's easy to see how something like this can happen. Even while taxiing extremely slow at times, we've skidded while exiting the runway or while just making turns onto taxiways. Glad it wasn't anything serious.
Even in the Arctic version of the RJ, I'd be hard pressed to taxi through a 5 foot snowbank. Probably the best strategy would be to pull a 180 in front of it and then run up the engines for a few minutes to melt it and then turn back around and taxi on through.
I fly in snow and through snow drifts in the sled everyday, and I'll tell you what, even when its groomed you've got to fly the airplane all the way to shut down. A little too fast and with a full load you've got too much momentum. A little too fast empty, and your brakes won't do the trick. All and all, its very difficult to operate safely in slick conditions if you're not used to it. Every landing must be done at the minimum safe speed, hurrying will get you in deep ####. When its icy, you can just haul ass down the taxi way unless you've got beta/reverse. And for you guys driving the hondo, remember the reverse, we used that at ACE in PABG several times just to maintain directional control on the ground as we were taxiing, the airplane would want to weathervane, or whatnot, and it'd be a battle to make it work. Better to be slow and safe than slide into the ditch.