On occasion, handlers will also encounter the following conditions when on a search.
Looping is sometimes found in still-wind conditions. When this occurs, the scent is carried on an upraft above the subject, transported aloft for a few hundred feet (or farther), then dropped back down. The dog will alert but then lose the scent because there is none between the subject and the point where the scent dropped. It is this situation that makes the recording of alerts so important. If one or more dogs alert in an area without making a find, that area should be rechecked on a fairly close basis. If the alert was recorded by a handler who was only halfway through a sector, however, the continuance of a normal search pattern will often resolve the problem.
Chimney Effect and Eddying
The chimney effect is the upward air flow caused by warm air (see Drainages). Eddying occurs along cliff walls, tree lines and similar obstructions and may disperse scent in several directions. While scent in these conditions may cause some confusion for the dog, a skilled team should have little trouble working it through. Handlers should not be so concerned with these factors that they continually alter their search plan to compensate.
Low areas collect scent, just as they do water. As with looping, a scent pool may produce an alert that the dog cannot work to its source because of shifting winds. These alerts must be marked on both the handler’s and the base maps. Handlers should assess the terrain to see what features may have funneled the scent to that particular locations. When evaluating possible origination points, bear in mind that scent can be carried for long distances before it pools. Pooling is frequently seen in the cool evening hours when the air flows downhill and may well be encountered during a night hasty searches of drainages or similar terrain.
Few of the above conditions will deter the well-trained dog/handler team. Do not use these scent behaviors as excuses for poor performance. To be sure, wind and terrain can combine to cause a dog to miss the victim, but such occurrences are extremely rare.
Experienced handlers learn to adapt their strategy to the existing conditions and experienced dogs learn to range persistently to find the source. As you start training your dog, you must be aware from the very beginning of wind velocity and direction, along with the effect terrain has upon this. Your dog’s success will depend upon your knowledge of how to approach each problem.