Foehn and forest fire in Mazandaran and Gilan provinces A case study: the forest fire from December 16 - 21, 2005

In December 16 – 21, 2005 occurred a wild spire forest fire on about 150 hectares of Gilan and Mazandaran forests. In regarding to study of these less precedence fires, data of frequency, area and time of fires and also their synchronized meteorological data were obtained. The following results are based upon the analysis of the weather pattern of the fire period by using Franciele method and synoptic-dynamic analysis in the study period: during the fire relative in the lee slopes of Alborz relative humidity decrease to %20 and temperature increase to 25◦c and in the windward slopes have occurred precipitation and also cloudy conditions. For this reason it seems föhn event has been main factor of fire. Also in the period the calculated Franciele coefficient (k) shows high dangerous stage of fire ability (0.3