100 years since the biggest avalanche tragedy in Slovakia in the Rybô village - reanalysis of weather conditions

The winter at the turn of the years 1923 and 1924 in the highest elevated areas of the Slovak mountains was exceptionally rich in snow, leading to an increased occurrence of avalanches. The deadliest avalanche not only in that season but in the entire history of Slovakia occurred on the night of February 6, 1924, from the southeast slope of Mount Krížna (1,574 m above sea level) in the Veľká Fatra mountain range. 
In the presented contribution, we try to analyse the meteorological and snow conditions that led to this tragic event. The assessment of the weather situation was carried out based on the NOAA-CIRES reanalysis of the 500 hPa geopotential, surface pressure field, and temperature at 850 hPa. In addition, 103 precipitation and 10 climatological stations were used for the analysis of snow cover height and for the validation of the NOAA-CIRES reanalysis.
According to available data, the deepening of low-pressure systems over the Baltic states played a crucial role in creating suitable conditions for avalanches, associated with a frontal passage over Slovakia from February 2nd to 6th, 1924. A northwest cyclonic situation prevailed, during which a significant amount of snow fell on the northwest (lee) slopes of the mountains due to orographic lifting in a relatively short period. This effect was observed on the ridge of the Veľká Fatra and also in the area of Krížna, where around 60 cm of new snow fell in 4 days. Due to the absence of trees or other vegetation that could increase surface roughness in this location, the snow was easily transported by the northwest wind to the leeward side of the mountains, creating conditions for snow cover accumulation on the eastern slopes.
The temperature at the 850 hPa level was below freezing from February 2nd to 5th. However, on February 5th, 1924, a warm front passed through, leading to a short-term significant warming, combined with extremely intense snowfall driven by west to northwest winds, which transported snow into the release zone with predominantly east exposure. Here, the previously above-average snow cover height created suitable conditions for avalanche initiation.
The avalanche in the settlement of Rybô destroyed 3 houses and damaged 2 others. It buried 22 people, of whom 18 (including 15 children) did not survive. The amount of snow in the avalanche was so significant that it did not melt even during the summer. The avalanche was approximately 2.5 km long and descended a vertical distance of 760 m. It generated very high impact pressure and speed (up to 180 km/h). According to today's international avalanche classification, this avalanche would be classified as a very large avalanche, which is the largest size category.