There are substantial areas of Mollisols in central USA, some of which have seasonal snow, and severe erosion as gullies. Kansas, Nebraska, Iowa, western Missouri, some areas in other States like Colorado I am familiar with some of these areas. I have not studied whether snowmelt specifically is important, but I have seen freeze thaw cycles important as well as high intensity storm events. It has been shown that channel morphology and highest sediment loading tends to be at bankfull, but since gullies have no floodplain, maximum stream power is probably exerted at episodes of bankfull and above. If snowmelt drives the peak flows, such as at higher elevations, then it probably when combined with highly erosive and disturbed farmland soils, it Could be a main factor in rill and gully erosion. Anyway the central and north central USA plains with mollisols and higher elevations, which are farmed may be similar. I know some of these areas have had gully research and papers. One name from USFS Research that comes to mind is Burchard Heede at Rocky Mountain Experiment Station and his Alkali Creek Study area in Colorado, which had snow and gullies, past farming or pasture, but don’t think soils were Mollisols. Colorado also has what they call a summer monsoon season, and many of the central USA states have strong thunderstorms with intense rainfall events. Snowmelt may be important for some areas, but not so much in others.

William F. Hansen

Thank you, William, for sharing of the nice opinions and experiences. I agree with that in most places, freeze-thaw action plays a more important role in soil erosion. There are 3 or 4 Mollisols areas in the world, including the central USA, and the Northeast China. I think, the locations are related to climate. So, the seasonal snowmelt erosion might be occurred in these places. And many parameters could affect the amount and proportion of snowmelt erosion. For example, the distance to the sea, a higher slope, different tillage way, ... Maybe snowmelt erosion is much more obvious in high latitude and altitude regions, like Canada, North Europe, the Alpes, where have more research and papers. In my opinion, at least in Northeast China, seasonal snowmelt erosion is severe, and also could intensify other soil erosion, which may be called compound erosion. I will read the research of Burchard Heede. Thanks again.

Gully Erosion Induced by Snowmelt in Northeast China: A Case Study

https://www.mdpi.com/2071-1050/11/7/2088/htm

This article mentioned some of those area:

the Schafertal Basin in eastern Germany, the Peace River Basin of British Columbia, the Pacific coast of the northwestern United States, and Fosheim Peninsula of Canada.

Shah-Al Emran Thank you, Shah-AI.It is a good research and reference.

I have dealth with this for the Czech and Slovak Republic area. Content of suspended solids analysed in several Czech and Slovak rivers exhibits two peaks: in summer caused by heavy rainfall, in spring caused by snow melting. As a critical period were identified after harvest and snow melting period (August-April). Methodology of average annual soil loss estimation caused by rainfall and snow melting is presented in this conference paper: https://www.researchgate.net/publication/337567801_Calculation_of_average_annual_soil_loss_in_nongrowing_period_for_South-Moravian_region_using_USLE-GIS_method

Jiri Brychta Thank you, good information for me.