High winds are sometimes found in low-altitude terrain in mountain valleys. The reasons for this and the possibilities to find such sites from modelled wind fields are investigated. The higher-order closure MIUU model developed at Uppsala University is used for a general study of channelling of winds in mountain valleys. The importance of length, width and depth of the valley is investigated. Comparisons are made with wind measurements. Copyright © 2006 John Wiley & Sons, Ltd.