The snow was soft enough to ball under the horses' hoofs, so that most of the time the poor animals skated and stumbled along on stilts.

Thus we made our way back over ground which, naked of these difficulties, we had considered bad enough.
Imagine riding along a slant of rock shelving off to a bad tumble, so steep that your pony has to do more or less expert ankle work to keep from slipping off sideways.

During the passage of that rock you are apt to sit very light.

Now cover it with several inches of snow, stick a snowball on each hoof of your mount, and try again.

When you have ridden it--or its duplicate--a few score of times, select a steep mountain side, cover it with round rocks the size of your head, and over that spread a concealing blanket of the same sticky snow.