Natural hazards are involved in various factors and circumstances, including natural hazards such as heavy rainfall and floods. Various factors and situations are involved in the occurrence of natural hazards. These natural hazards include heavy rainfall and floods. In the present study, in order to evaluate the synoptic conditions for the occurrence of flood-induced rainfall in Khalkhal city, in Ardabil province, first the statistical data of 34 year rainfall was used from 1987- 2020. The most rainfall occurred in date 1991.09.12. The synoptic atmospheric maps of this date at the level of 500 mbar including sea level pressure map, geopotential elevation, wind speed and direction, humidity, temperature, surface rainfall and blocking (omega), using satellite imagery received and reviewed from the NCEP/NCAR database of the US National Oceanic and Atmospheric Administration. In this research, Environmental approach to Circulation method was used. Based on the results of the present research in the study of atmospheric synoptic maps showed that in addition to atmospheric and terrestrial conditions effective in causing heavy rainfall in the study date, the internal situation with an external pattern such as the surrounding seas and neighboring Iran such as the Black Sea and the Mediterranean has had an impact. The amount of monthly rainfall of Khalkhal station as a region in the south of Ardabil province and southwest of the Caspian Sea, with more rainfall in the three months of spring including March (1321.8 mm), April (1716.7 mm) and May (1448.5 mm). The highest natural atmospheric hazards due to heavy rains and floods in the study area were urban, rural, riversides and agricultural damages in the mentioned months. The maximum and minimum rainfall are 51 and 4.5 kg/m², respectively, but in the study area, the curve shows the number 20 kg/m² and this indicates the formation of super heavy rainfall. The observable temperature values with Kelvin criterion in the study area were significant, the maximum and minimum values are 265 and 245 degrees Kelvin, respectively.