At higher flow, the crests erode due to the higher speeds and momentum and deposition occurs farther down the lee slope. Thus, high flow ripples have rounded crests. This is the truly distinctive feature and can be present even if the ripples are not very symmetric. Storms - Storms produce both large waves and strong, irregular currents. The combination and interference of these produces some unique deposits which can be used to recognize the importance of storms in a given marine sequence.
Storms generally start far from shore and can approach through time.
Then they either die out or move on. For example, sharp crested wave ripples might transition into round crested wave ripples, followed by cross stratification due to large waves and strong currents, followed by erosion, deposition of the coarsest sediment, and a reverse of the sedimentary structures. However, because there is usually little sediment being deposited at the beginning of a storm because there is not much sediment in motion and because flow speeds are increasing, there is usually no record of the first half of this sequence in the rock record. It is only the second half that gets preserved. 10's of cm across.