A recently formed gully in a terrace of the Öreälven River, northern Sweden, is an example of an erosional feature that developed in silts and sands overlying glaciofluvial scdiments. During work in a gravel pit, glaciofluvial gravel at the edge of the terrace was removed and the silt and sand on the eastern side were exposed. In connection with the spring flood in May 1983, the groundwater level rose and groundwater started to seep out, causing rapid gully erosion. In two days, about 10000 m3of silt and sand were removed by erosion and deposited as a large alluvial fan below the gully.