How to Signal for Help in the Wilderness

Know that any series of three signals is a universal call of distress: Three whistle blasts or three gunshots, for instance, will alert others that you need help.

Understand that yelling is only effective if people are nearby. The human voice doesn't carry well, so save your vocal cords and strength.

Find a clearing or hilltop and start three signal fires, making sure to keep them under control. Place them in triangular form (a known signal for help) and space them 50 feet apart so that a plane can distinguish the pattern from overhead.

Use green and wet wood to send up ample smoke during daylight; use dry material at night to make a strong, roaring blaze.

Spread out three sets of brightly colored equipment'for example, a tent cloth, a tarp and a space blanket'in an open space to signal your distress. Again, put them in triangular form.

Use brightly colored gear or dark brush or rocks to create three piles, or lay out an 'SOS' or a big 'X' on an open snowfield to signal aircraft rescuers in wintry conditions.

Use a mirror to flash a sunlight signal over long distances if you see a plane or people in the distance. (This technique won't work on cloudy days.)