Spearfish Creek is a fast-moving creek that emerges from Spearfish Canyon at Spearfish. It runs roughly south to north through the center of town (parallel to Canyon Street), year round. The creek freezes from the bottom up instead of icing over. This unusual phenomenon occurs due to the very fast rate at which the creek flows. This speed prevents ice from forming except along the bottom of the creek bed where friction and turbulence allow the water to slow down long enough to freeze. Since the creek continues to flow atop this ice, the water level of the creek gradually rises as more ice accumulates on the bottom, in some cases causing flooding on the north side of town where the channel is not as deep.