Methods of long-range forecasting of dates of the spring flood beginning and peak flow in the estuary sections of the Ob and Yenisei rivers

Multi-year characteristics of the beginning of spring floods and their peak flow observed at the stream gauges located in the estuary sections of the Ob and Yenisei rivers in the period from 1936 to 2003 were obtained in this work. For most of stream gauges, significant correlation between these characteristic dates and dates when the accumulated positive temperatures (observed at the meteorological stations located in the middle parts of the catchments) reached 30 and 40°C was revealed. A great percentage of successful forecasts issued by using the multiple regression equations (78–86%) allow recommending using the obtained relationships for long-range forecasting of dates of the spring flood beginning and its peaks in the estuary sections of the Ob and Yenisei rivers with a 20–24-days lead time.