In the paper, the use of cartographic research method for the analysis and generalization of materials describing extreme events associated with rarely recurring high water and flooding in river basins of the Upper Ob is proposed. Basing on statistical data obtained from municipalities of the adjacent regions (Altai Krai, Republic of Altai, Kemerovo, Novosibirsk and Tomsk oblasts), including the information provided by territorial bodies of the RF Emergency Situations Ministry, we created a database for assessing actual and probable damage to population and economy of the study territories. Actual damage is generalized and analyzed in the context of river basins and municipalities of the entities, i.e. subjects of the Russian Federation. In order to assess probable damage, cartographic sources, including open data from the Internet as well as modern software tools were involved. The estimation of probable damage to population and economic objects was performed by the example of settlements (including those suffered from extreme flooding of 2014) located in the Charysh basin (Altai Krai). For that GIS projects and a series of damage evaluation maps were created. River basins of the Upper Ob regions were ranked according to recurrence frequency of extreme events and the extent of actual damage to population and economy there in 2004–2018. On the basis of these results, recommendations to prevent emergencies caused by the negative impact of water were developed.