The vulnerability of the population to various kinds of hazards varies significantly over time. In this paper, the authors attempt to link the sporadic pulsations of the population under the influence of the events of the Day of the City of Moscow in 2018 with the potential risks of emergency situations for residents and guests of the city at this time. The study was based on the use of data from mobile operators on the placement of the population during the holiday period. Based on this, quantitative vulnerability assessments are made, and high-risk areas are identified. It was shown that during the festival period, the potential threat is distributed unevenly throughout the day and correlates with the main points of tourist and leisure attraction. In particular, in the areas of Red Square, Zaryadye Park, Tverskaya Street, Luzhniki Stadium, Poklonnaya Gora, Sokolniki and Izmailovo parks, as well as on the territory of VDNH, the potential danger increased three times during the day.