This paper proposes a reliable wildfire monitoring system based on a wireless sensor network (WSN) sparsely deployed in adverse conditions. The physical environment under consideration is characterized by asymmetric, irregular, and unreliable wireless links, inadequate Fresnel zone clearance, and routing problems, to name a few. We use reliable communication schemes on a fault-tolerant network topology, where sensory data are guaranteed to reach the base station with organized data storage and real-time visualization. Our approach has been validated experimentally for the case of peat-forest wildfire in southern Borneo where the fire breaks out frequently.