quote Blatz: "I'm just getting into Backcountry skiing (I've been a long time skater). Is an adjustable pole needed for mainly flat terrain? I know it's a good idea if you will be encountering slopes along the way. But I'm also seeing varied snow depths are a another reason for an adjustable pole. If it's a good idea to have one , what are some good options?"
I don't think it's necessary. But I ended up buying the Fischer variolite adjustable poles anyway. They are really nice. The reason I got them, was that I was having a hard time finding longer nordic poles with full baskets at any local shops - everythings a racing pole. There wasn't much price difference after shipping between the non-adjustable versus adjustable poles, so I went adjustable.
I think Fischer and Rossi sell 2 piece adjustable poles geared more towards Nordic skiing. Most of the 3 piece adjustable "backcountry" poles are too short for nordic skiing, and IMHO seem weak when extended to their maximum length.
The only thing I used the adjustment for last year, was to tighten my tarp. A single pole could be extended long enough that I could use it as a tarp center pole.