At the junction of two seasons — in the late fall and early winter, as well as rapid warming during the cold period is probably a rare occurrence, as freezing rain.
Some call freezing rain solid precipitation in the form of ice, falling at low temperatures. But this is not quite true. Freezing rain occur when the temperature is kept below zero. And for their loss requires that over the cold air near the ground is frozen wedge of warm air with plenty of steam. In this case, a drop from the top layer, falling down, closer to the ground will be supercool and solidify in the form of ice.
Freezing rain often falls on the east coast of North America where there are cold air from the west and the warm and humid in the east. For example, in 1998, freezing rain in Canada was more than three days, during which time rainfall exceeded the annual rate twice!
As for Russia, in its central regions of freezing rain — a rare phenomenon. They are most likely to occur in the south and west. The reason is that the warm air masses come to us from the Atlantic Ocean or the Mediterranean Sea. Therefore, freezing rain likely shed more "Western" Smolensk than in Saratov, where the influence of the Atlantic lower. But in Siberia, dominated by anticyclones and frost, such a phenomenon is impossible.
In Moscow, freezing rain for the first time weather observations took place in December last year. Then he brought a lot of troubles. Under the weight of ice crust broken branches and fallen trees, broken off harness. Several dozen people from falling tree injured. Layer of ice covered roads, resulting in numerous casualties.
Predict an anomalous natural phenomenon, as freezing rain, useless. But you can not count myself a rain, and the weather conditions under which it may spill.
Alexander Kislov, Professor, Head of Department
Meteorology and climatology geographical Faculty