If the reference points are few and or the weather suddenly limits the view it is important to know where you are. Lost is lost, and a compass and map will not find you. Know where you are before you loose reference points or targets. Lets assume you have set up camp on a high alpine meadow, and before going to bed you were able to mark the site on a map. Next morning the cloud ceiling has dropped and you barely see the end of the tent.
Lets see, set the back edge of the compass on the camp and the front edge to the center of the pass.
The bearing is 219. Now its time to remember that formula from the great wilderness navigation course you took last year. The map says that the magnetic declination is 20. Take down camp, set the compass at 199 degrees and confidently lead the group to the pass. Now if you do get lost with a map and compass all is not lost.