The Wolds area takes the form of an elevated, gently rolling plateau, cut by numerous deep, steep-sided, flat-bottomed valleys of glacial origin. The chalk formation of the hills provides exceptionally good drainage, with the result that most of these valleys are dry. Surface water is quite scarce throughout the Wolds. At Flamborough Head the Wolds rise up to form high chalk cliffs, where there are water-worn caves and stacks along the shore. Flamborough Headland is designated a Heritage Coast. Coastal erosion around Flamborough Head has led to visitors being warned by the Humber Coastguard to be very careful on coastal paths.