Tamalpais's western part is heavily forested with tall redwoods and Douglas firs. The same fact holds for the steep, south-facing bowl canyon that Muir Woods is located in, with precipitation in Redwood Canyon at around 39.4–47.2 inches (1,000–1,200 mm). As in San Francisco, most of the annual precipitation falls during the winter months. During cold, wet winter storms, the mountain also regularly gets some snowfall, sometimes as much as overnight, as observed in February 2001, March 2006, and February 2011. The region sometimes gets hit with strong Pacific storms that may topple trees, and bring hurricane-force winds to exposed, barren areas like the Bolinas Ridge and the summit of Mount Tamalpais. In summer, the area gets almost no precipitation, except for fog drip that occurs in Muir Woods, the Bolinas Ridge and the western end of Mount Tamalpais, where summer fog and oceanic breezes are more prevalent. In contrast, the eastern foothills, sheltered from the oceanic breezes and fog, are drier, since the foothills force little moisture out of the air. This leads to the fact that the eastern slopes contain only oak, pine, chaparral shrub, coastal sage scrub, grassland and sparse Douglas-fir forest. Coastal sage scrub also occurs on some of the exposed coastal slopes. Temperatures on top of Mount Tamalpais are generally somewhat cooler than places next to the San Francisco Bay or the ocean due to elevation. In summer, however, the top of Mount Tamalpais may actually be warmer than the middle, foggy elevations due to a thermal inversion. The summer fog and breezes make locations on Mount Tamalpais, closer to the ocean, cooler than the blazing hot interior valleys. Plant communities Hardwood woodland types are generally subtypes of California oak woodland, including oak-bay-madrone forest, oak woodland, and oak savannah. Oak-bay-madrone forests are found in areas with moderate moisture and particularly favor north-facing slopes. They are dominated by one or more of three hardwood tree species – Coast Live Oak, California bay, and madrone. Coast live oak tends to be dominant in somewhat drier areas, while bay is more dominant in shadier, moister areas; madrone is abundant in certain soil types in both moist and dry spots. Oak woodlands are a more open-canopy forest dominated by coast live oak, while oak savannah has a completely open canopy and represents a mixture of coast live oak woodland and grassland. The great diversity of microclimates on Mount Tamalpais ensures