and the average morning minimum is in the 50s (10-15 °C). Thunderstorms are frequent during the warmer months. Frosts and freezes can occur any month of the year. Winters are typically cold, windy, and snowy. Minimum temperatures can drop to -30 °F (-34 °C). The average seasonal snowfall is estimated to be around 150 inches (381 cm). In exceptionally snowy winters, large drifts of up to 20 ft (7 m) can form, lasting in sheltered locations into May. Due to high elevation, frequently located at cloud level, spectacular rime ice is frequently seen totally coating the forest in pure white. Despite the overall vigorous winter, the relative southern location (39th North parallel) allows for occasional intrusions of warmer, well above freezing air from the Gulf of Mexico. Thus, rain can occur during even the coldest winter months. During one of the snowiest winters in history (2009–10), about 275 inches (700 cm) of snow is estimated to have fallen above 4,000 feet (1,220 m). This section of the Allegheny Front is one of the windiest spots east of the Mississippi. The effect of these winds can be seen in the flag-form red spruce trees; their branches grow mostly on one side (east), away from the prevailing west winds. Because of the drying influence of the winds, stunted branches are produced on the west side of the tree above the protective shrub layer. Stunted branches on the east side give the trees a twisted appearance. Where spruce are protected by a shrub layer, luxuriant webs of branches extend for a radius of a dozen feet, giving a mat-like look to vegetation. Ecology Flora Dolly Sods is well known for its open expanses of sphagnum bog, heath shrubs and scattered and stunted red spruce – all creating impressions of areas much farther north. Many plant communities are indeed similar to those of sea-level eastern Canada. But the ecosystems within the Sods are remarkably varied. In recent decades, the many stages of ecologic succession throughout the Sods have made the region one of enduring interest to botanists. Sods (grass balds) The local term "sods" is a traditional name referring to several high-elevation meadows in the High Alleghenies. The term is virtually synonymous with the "grass bald" of the southern Appalachians. These grassy areas on mountain slopes or summits apparently existed by the scores in the mid-Appalachian region when first discovered . According to botanist