The distress signal is three short, sharp whistles or calls repeated at intervals. Do not use anything that sounds like it unless you are in need. In calculating how much time to allow, consider altitude and obstruction along with distance. People who walk 3 miles an hour on the level will normally go up hill at around 1. Minor rock problems, willow matting, bogs, windfall, ice, and other obstructions decrease speed incalculably.
Darkness is an especially limiting factor.
When a swift stream must be crossed, No. 2 person belays from the shore while No. 1 person crosses a full rope length downstream, tied in and leaning slightly against the rope. He then takes upstream position to belay No. 2. Climbing alone in the mountains is not for the inexperienced. If you do it, leave word where you are going and stay with your plan. Keep a wide margin of safety in your movements.