In 1957, P.R. Steele, R.F. Marks and W.W. Tuck of the University of Cambridge embarked on an expedition to Tarso Tieroko, which Thesiger had described as probably the most beautiful peak in Tibesti, and which offered an interesting climbing opportunity. They started at the wadi Ybbu Bou and hired guides and camels for the three-day journey. Following a week of exploring the southern flank of the mountain and climbing the two peaks situated on a ridge to the north, they attempted to summit Tieroko from their camp at Wadi Modra. After ascending to an elevation of , just from the summit, they were faced with a vertical, crumbling rock wall, and thus were forced to descend. Following this defeat, they took the opportunity to climb Emi Koussi, 19 years after its first ascent by Thesiger, and also Pic Woubou, a prominent spire located between Bardaï and Aozou.