February 1929 – extreme cold especially in the central and eastern midlands
January 1929 was already quite cold. February, however, brought freezing temperatures, so that Lake Constance, for example, froze over. The night of February 12, 1929 then brought temperatures that had never occurr in the lowlands before (reliable data exist since around 1864) and did not occur again afterwards. At that time, very cold air flow from the east to the northern side of the Alps. According to a reanalysis by the ECMWF, the temperature in the free atmosphere at 850 hPa was -20 degrees. It was probably even colder at lower altitudes, because on the Schwäbrig, which is 1156 meters high, -25.2 degrees were record on the morning of February 12. This is very cold, but was even lower on February 10, 1956, with -27.8 degrees.
[°C ] at 850 hPa on February 12, 1929 06 UTC. At that time, very cold air was flowing from the east to Switzerland.
Ground pressure [hPa] and temperature [°C ] at 850 hPa on February 12, 1929 06 UTC. Very cold air was flowing from the east to Switzerland at that time. (www.wetterzentrale.de)
Clear night and snow cover significantly intensifi the cold
In contrast, records were record in the lowlands in terms of minimum temperatures. Firstly, the reason for this was that the night was clear, so that the already very cold air cool even further due to the negative radiation balance. Secondly, there was a blanket of snow over the eastern midlands, which greatly ruc the flow of heat from the ground, as snow has a strong insulating effect. As a result, the temperature in the lowlands fell to well below -30 degrees. The lowest temperatures were report in Beromünster and Unterägeri at -37 degrees, and in Dübendorf and
Schönenberg ZH at -35 degrees. It was also very cold paraguay phone number library in Affeltrangen TG and in Kollbrunn in the Tösstal at -32 degrees, in Urnäsch at -31 degrees, in Eschlikon at -30 degrees and in Lachen SZ at -29 degrees. It should be not that the measurements were not taken at official temperature measuring stations, but at precipitation stations, which also had a thermometer, or in the case of Dübendorf, it was a statement from military personnel at Dübendorf airport. Therefore, absolute accuracy cannot be guarante. However, the order of magnitude seems to be correct, because even the “official” stations occasionally record lows below -30 degrees. The “official” lows report were: Winterthur -30.5 degrees, Frauenfeld -28.8 degrees, Aarau -27.0 degrees and Lucerne -26.0 degrees.
Minimum temperatures at select stations on
the morning of February 12, 1929. The precipitation the new audience group that was just creat stations (top row) only measur the temperatures to whole degrees and only at the reading time awb directory of 7:30 a.m., so the temperatures are correspondingly inaccurate; the minimum temperature may well have been even lower. The “official” temperature measuring stations in Winterthur, Frauenfeld, Aarau and Lucerne had minimum thermometers, so the minimum temperatures were determin more accurately there.
Minimum temperatures at select stations on the morning of February 12, 1929. The precipitation stations (top row) only measur the temperatures to whole degrees and only at the reading time of 7:30 a.m., so the temperatures are correspondingly inaccurate, and the minimum temperature may well have been even lower. The “official” temperature measuring stations in Winterthur, Frauenfeld, Aarau and Lucerne had minimum thermometers, so the minimum temperatures were determin more accurately there. (MeteoSwiss)
Despite the icy cold, many people ventur out onto the frozen Lake Zurich in February 1929.
