Abstract: The extremum distribution of winter wind,the mean wind speed probability distribution and the wind hours of snowdrift at Naohai wind zone of Jimunai County,Xinjiang,China are studied using extremeⅠtype distribution and WeiBull distribution.The magnitude of wind-blown snow is quantified using the extreme value,the average probability distribution area and the wind-blown snow hour.The computed wind-blown snow magnitude is included for the road engineering design in the areas affected by wind and snow.The conclusion shows that the calculation of the snow protection engineering grade based on the mean wind speed of WeiBull distribution and the effective time distribution of wind-blown snow is a feasible method for the snowdrift prevention and control engineering on the highway.The design of the snow prevention projects does not have a clear design level with the reoccurrence period as an indicator,but only exists the magnitude of the disaster prevention and control. The extremeⅠtype distribution can be used as load calculation of snow fence,but it could not fit in the magnitude calculation of wind-blown snow.Using WeiBull distribution to calculate the effective blowing time and the average distribution of wind can effectively express the intensity of the wind-blown snow.Through this pattern,we can cipher out that the effective wind and snow blowing time is 88.74 days and the wind and snow magnitude is 452 m³·m^-1 at the zone.

Key words: highway, windblown snow, snow fence design, design frequency, Jimunai County