Sometimes several dogs in the field will establish the line over half a mile or so in this way, pointing to the subject. Wind carries scent to the dog, but also disperses it. Convection disperses it too, even more so. Only 100 ft. Areas searched morning and evening are much higher than midday in summer.
Dogs navigate most brush better than most people.
Dogs tire in deep powder snow, but the heavier coated breeds will still search. The handler will bring some, but on an extended search you should get a 50lb bag of the handler's brand for your teams. Dogs will need at least as much water as the handlers. If there are streams, springs, etc. But in dry country they'll need water rations too.