THE FREYSNES WINDSTORM

A devastating windstorm in SE-Iceland is studied with the help of observations from automatic weather stations and high-resolution simulations. In this windstorm there is at the same time a strong downslope acceleration of the flow and acceleration at the edge of the mountain. The downslope windstorm is associated with strong wave breaking below a reverse wind shear in the lower troposphere. The method of Brasseur is applied for calculating the gusts. In the downslope flow, the mean wind is underestimated by the model, but a high observed gust factor is reproduced in the calculations. In the corner wind, the mean wind is reproduced, but the gust factor is somewhat underestimated by the calculations