The formation of ice on rivers can cause discharge values to appear unusually high. Display of these erroneous discharge data may result in improper assessment of flow conditions and misuse of the data. For this reason, display of discharge values for rivers significantly affected by ice may be disabled from view. Even though the discharge hydrograph is disabled the most recent instantaneous value is listed above the graph and may be affected by ice. That Display of discharge data will resume when ice conditions are no longer present. Discharge values for rivers minimally affected by ice will continue to be displayed. Flows for rivers with these conditions appear to increase during the day and decrease during the night.