Study of spatial and temporal distribution of frost and sliding in Iran’s mountain roads using climatic conditions matrix (Case Study; Karaj – Chalous Road)

Abstract

Frost and sliding in Iran’s mountain roads cause dangerous conditions for road transportation. In this study,
two goals are followed: Firstly, description of a method for a determining the likely occurrence of the critical
condition of frost and sliding using the climatic conditions matrix along the Karaj- Chalous road (which is full of
– traffic and mountains roads of Iran, connecting the Northern provinces to Tehran the Alborz heights).
Secondly, the spatial and temporal analysis of frost using statistical analyses and GIS. One of the most
important conclusions of the study is that there is a direct connection between the frost and height phenomena
as by increasing the heights, the frost phenomenon occurs as soon as possible and is prolonged. From the
viewpoint of spatial distribution, the studied mediate parts (that is, Karai’s kms 43 to 128) are affected by drastic
frost and from the in viewpoint of temporal distribution the N5, N6 and N9 conditions (accounted as dangerous
frost conditions for transportation) have been concentrated in December, January and February.