It is narrated from Sa'id (may Allah have mercy on him) that Ibn Abbas (may Allah be pleased with them both) was on a journey and with him were a number of the Companions (may Allah be pleased with them), among them Ammar (may Allah be pleased with him). He led them in prayer while he was in a state of tayammum.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1110