A question for those who don't use a GPS: What's your S.O.P. for white-outs ? especially when wind whipped in winter and above tree line ? If you could be so kind as to describe what you actually do and not the theories behind what can be done. I see little or no use of wands, trailing ropes or map and compass in these conditions. Thanks.
The following events occurred well before anyone even heard of GPSes:
My first ascent of Mt Washington was in blowing fog with visibility often down to 50ft or less. (Via Tuckerman Ravine in summer, so snow wasn't an issue.) There were two of us--one would wait near the last cairn while the other went to search for the next. (Cord or rope could have been used as a tether to keep the searcher from getting lost, but we probably didn't have any.) There were enough short gaps in the fog that we were always able to spot the next cairn. (The only way that we realized that we were getting close to the summit was the car noise from the parking lot.) We chose to descend via the Auto Road which was easy to follow in the dark and fog (we also didn't have any lights...).
The trails near Mt Washington are extraordinarily well marked with frequent giant cairns and yellow paint and are fairly straight so it was pretty easy to guess where the next cairn was likely to be. If the trail had not been so well marked, we probably would have retreated.
On Katahdin Tableland in summer rain and fog, we once followed the wrong trail out of a junction until we came to a sign associated with the wrong trail... In winter, we were required to carry wands. We ascended Abol Slide, placed some wands marking its top, and walked across the Tableland to the summit. The slide is not visible from the Tableland (from the Tableland, three sides just drop out of view). The wands were helpful in full visibility and would be even more helpful in limited visibility. (The Tableland is pretty featureless--if the visibility was bad, we would have needed to follow a compass bearing to find the summit and probably would have placed a lot more wands.)
BTW, the Tableland of Katahdin is reported to have magnetic anomalies, so your compass is likely to be inaccurate.
Doug