a strong synoptic-scale squall line passed north to south over whole central and eastern Poland, precipitating both granular snow and snowflakes, with discharge intensity exceeding 100 per minute. Other recent occurences were in Poland and the Czech Republic in January 2023, Germany in January 2021, and Norway and Netherlands as well as Austria in April 2021, with previous occurrences in Norway in January 2019 and January 2020. In Stockholm, thundersnow occurred on the morning of November 21, 2022, and made the news. Low-pressure events in the eastern Mediterranean that originate from polar origin cause copious thundersnow occurrences during winter storms, especially over the elevated provinces of Israel and Jordan, including Amman and Jerusalem. When such storms happen at areas intended for skiing, the mountains are often evacuated for safety. The South Region of Brazil registered episodes of thundersnow in 1984 and 2005, in the state of Santa Catarina, and in August 2011, in some municipalities of the highland region of Serra Gaúcha, in the southern state of Rio Grande do Sul. It is also common around Kanazawa and the Sea of Japan, and even around Mount Everest. Formation Thundersnow is caused by the same mechanisms as regular thunderstorms, however it is much more rare during the winter because cold dense air is less likely to rise. Lake effect precipitation Lake effect thundersnow occurs after a cold front or shortwave aloft passes over a body of water. This steepens the thermal lapse rates between the lake temperature and the temperatures aloft. A difference in temperature of or more between the lake temperature and the temperature at about (the 850 hPa level) usually marks the onset of thundersnow, if surface temperatures are expected to be below freezing. However several factors, including other geographical elements, affect the development of thundersnow. The primary factor is convective depth. This is the vertical depth in the troposphere that a parcel of air will rise from the ground before it reaches the equilibrium (EQL) level and stops rising. A minimum depth of is necessary, and an average depth of or more is generally accepted as sufficient. Wind shear is also a significant factor. Linear snow squall bands produce more thundersnow than clustered bands; thus a directional wind shear with a change of less than 12° between the ground and in height must be in place. However, any change in direction greater than 12° through that layer will