An important environmental effect of a mountain concerns its shadow.
The range and intensity of this shadow varies, depending on the height and shape of the mountain, time of year and weather conditions. However, the shadow-effect may be less far-reaching than one would suspect. See these simulations, developed by Egbert Tigelaar, Immersiv3Dimensions.
A mountain, situated in the Markermeer:
A mountain, situated in the North sea, near the village of Bergen: