Always select an isolated tree so that you do not start a forest fire and endanger yourself. The international distress signal is three columns of smoke. If you practically smother a large fire with green leaves, moss, or a little water, the fire will produce white smoke. If you add rubber or oil-soaked rags to a fire, you will get black smoke. In a desert environment, smoke hangs close to the ground, but a pilot can spot it in open desert terrain.
Smoke signals are effective only on comparatively calm, clear days.
High winds, rain, or snow disperse smoke, lessening its chances of being seen. If you have smoke grenades with you, use them in the same pattern as described for fires. Keep them dry so that they will work when you need them. Take care not to ignite the vegetation in the area when you use them. Pen Flares These flares are part of an aviator's survival vest.