The climate is influenced by altitude with lower temperatures generally found at higher elevations. Subtropical forests dominate the lower elevations of the Hill region. Winds that flow over mountains down into lower elevations are known as downslope winds. Water boils at lower temperatures with the lower air pressure that occurs at higher elevations. The mapping yields onshore topography as well as underwater elevations. Annual precipitation amounts range from , with heavy winter snowfall in the higher elevations. Precipitation is seasonal and most occurs in the higher elevations. Annual rainfall ranges from with more in higher elevations. These mountains form a distinct highland rising to elevations above . Temperature, atmospheric pressure and humidity decrease in higher elevations. Precipitation is also somewhat less than farther south, except at some of the higher elevations. Vertical datums measure elevations or depths. Winters tend to be cold and wet with potential snowfall at higher elevations. Animals at higher elevations and latitudes emerge later. Snowfall is erratic and primarily affects the higher elevations.