Characteristics and causes of large-scale freezing in southern China in winter of 2007 -2008

La Nina phenomenon appeared in 2007, lasted until 2008, and reached its peak in February 2008. Under the influence of La Nina phenomenon, the cold air is strong in winter and cold in winter. Last year's snowstorm was not only caused by La Nina. Last year, blocking high pressure was formed in high latitudes in the northern hemisphere. Controlled by blocking high pressure for a long time, single weather often forms under blocking high pressure control, which is beneficial to the continuous southward movement of cold air. At that time, the subtropical high was located in the north, and the southerly airflow on the west side of the subtropical high was continuously sent to China. Moreover, the south branch trough is extremely active, and the water vapor is continuously transported to the southern part of China, and the intensity of cold and warm air is equivalent, resulting in a wide range of rain and snow freezing disasters.

Features:

1. Strong strength, wide range and long duration.

2. The power and communication networks have been severely damaged.

3. Roads and railways are interrupted, and the task of emergency rescue for stranded passengers is very arduous.

4. The task of resettlement and life support for the affected people whose houses collapsed and were damaged is very arduous.

This loss is rare in history.