Warned by scouts and Arkansas unionists, Curtis rapidly concentrated his outlying units behind Little Sugar Creek, placing William Vandever's 700-man brigade, who marched in 16 hours from Huntsville to Little Sugar Creek. But Curtis's right flank also suffered from Sigel's having sent a 360-man task force to the west, where they would miss the next three days of fighting. Sigel also withdrew a cavalry patrol from the road on which the Confederate army was advancing; however, Colonel Frederick Schaefer of the 2nd Missouri Infantry, on his own initiative, extended his patrols to cover the gap. When Van Dorn's advance guard blundered into one of these patrols near Elm Springs, the Federals were alerted. Still, Sigel was so slow in evacuating Bentonville that his rear guard was nearly snared by Van Dorn on March 6 as he advanced.