On the Modder River, Methuen's division of 15,000 frontline troops ran into heavily dug-in Boers on the Magersfontein Heights. The British artillery barrage warned the Boer of the impending assault, led by the Highland Brigade in the monsoon rains in the darkness. At dawn the British were caught by a murderous cross-fire. Major-General Wauchope became a high-ranking casualty. The British casualties were 1000 men to the Boers' 250. The defeat delayed the relief of Kimberley.