The Wind Gap of the Lehigh Valley is a great display of natural forces. A wind gap is a water gap in where the water source did not "survive" the complete erosion of the mountain. There is a hike up the Blue Mountain along the Appalachian Trail at the Wind Gap. The hike is steep, but very beautiful. The view at the top is wonderful in the winter or early spring, but may be very thick during the summer and fall. Left: View from Appalachian Trail along at the Wind Gap in mid-spring. Overlook is of eastern Lehigh Valley.   Right: Base of Appalachian Trail heading North. Trails are very rocky!