How could this happen?

Some powder, but we weren't sure where we were

I guess we weren't really lost.
I knew that Porphyry Peak was above us, O'Brien Creek below and the ski hill to the south.
But when we took our compass readings both Jim Heckel and I reckoned wrong.
We were skiing during the big storm on Wednesday in the Little Belts, having dropped off Porphyry to the north and looking for the North Bowls to do some turns.
I overshot them and ended up closer to the Moose Park area.
Jim recalled a snowmobile trail intersection that leads right to the bowls.
In the process of getting there we skied too far down the mountain and since we couldn't find the bowls, became a tad disoriented.
We backtracked to Jim's intersection and found the bowls.
We also found a lack of base in deep powder, making trail-breaking difficult.
I discovered some unstable snow as well and there was a small amount of collapsing.
That was enough for us, and rather than play with any avalanche on the 30 degree slopes, we got out of there and began looking for a route back to the ski hill.
With a great deal of effort we worked our way back up Porphyry.  It took forever and we never did arrive at  the ski hill run.
Then, we discovered our tracks, the tracks we thought we had skied down earlier in the day.  Thinking that we could follow them back to the ski runs we followed them and discovered they headed down the way we had come up.  We turned around the followed the tracks back down and ended up going back to where we had started our climb up.
It was very unsettling to discover we had may have skied in a circle.
From there it was easy to follow the snowmobile trail back to the ski hill and out.
I'm mystified about what happened.
Couple of thoughts:  I was glad we had a compass along to help us with directions.  A map would have helped.  It could have gotten dangerous.
The storm dumped a foot of snow on Great Falls and temperatures plunged to zero.