message and have it understood, both the signaler and the recipient must make successful proficiency checks. If one fails his roll, the message is distorted; the message can be sent again in the following round, and proficiency checks may be attempted again. If both checks fail, or if either character rolls a natural 20, an incorrect message was sent and received; the message has the opposite of the intended meaning. Characters without the signaling proficiency, as well as characters who have the proficiency but use a different signaling method, can't understand the signals.
A character with this proficiency has a thorough understanding of caves and underground passages, including their geology, formation, and hazards. The character generally knows what natural hazards are possible and what general equipment a spelunking party should outfit itself with. A successful proficiency check can reveal the following information:
Determine, by studying cracks in the walls and pebbles on the loor, snif ing the air, etc., the likelihood of a cave-in, flash flood, or other natural hazard. This only works with respect to natural formations, and is negated if the natural formations have been shored up, bricked in, or otherwise tampered with.
Estimate the time required to excavate a passage blocked with rubble.
While exploring extensive underground caverns, a successful check reduces the chance of getting hopelessly lost when confronted by multiple unmarked passages, sinkholes, etc. to a maximum of 30%, assuming good lighting (see DMG Table 81-82).
By notching trees, scattering pebbles, piling stones, and clipping weeds, the character can mark a trail through any wilderness area. Providing he moves at 2/3 his normal movement rate, he can mark a continuous trail as long as he likes; however, the longer the trail, the less likely he'll be able to follow it back.
A successful proficiency check enables a backtracking character to follow his own trail for a distance equal to his level in miles. If he fails a check, he loses the trail. For instance, assume a 3rd level character marked a 12-mile trail. His irst successful proficiency check enables him to follow this trail back three miles. A second successful proficiency check means he can follow the trail another three miles. The third check fails, and he loses the trail; he's only been able to follow his trail for a total of six miles.
The tracking proficiency isn't necessary to use the trail marking proficiency. However, when a ranger loses his own marked trail, he may still attempt to follow it using his tracking proficiency. Any other characters with the tracking proficiency may also attempt to follow a ranger's marked trail, using the rules applicable to the tracking pro iciency.
A marked trail lasts unless it is obscured by precipitation, a forest fire, or the passage of time (an undisturbed trail marked in a forest should last for weeks, while an arctic trail