about one million years ago. The hard, erosion-resistant Pottsville Formation of sandstones is the higher layer supporting the mountains surrounding Canaan Valley and also constitutes the sharp rim of the nearby Blackwater Gorge. Tombstone-like outcroppings of Greenbrier Limestone are also exposed at places along the Valley floor. A relatively high area within the Valley – the Central Pocono Ridge – is composed of the erosion-resistant Pocono Group sandstone. Climate Because of its relatively high elevation of 3,200 feet, Canaan Valley has a cooler, moister climate than surrounding areas at lower altitudes. Summers are cool and humid with afternoon maximum temperatures averaging in the mid 70s °F. Summer morning minimum temperatures average in the low to mid 50s °F. The average growing season of about 95 days is shorter than in Fairbanks, Alaska in interior central Alaska. Winters are typically cold and snowy with an average winter producing of snowfall. The largest snowfall of was recorded in the 1995–96 winter. Even in the mildest of winters, over of snow falls. Snow pack usually reaches a maximum depth of about or more in late February. In exceptionally cold snowy winters, packs can exceed in depth in the woods. Due to its proximity to both the warm Gulf of Mexico and frigid interior northern Canada, periods of warm above freezing conditions alternate with frigid temperatures. This results in periods of rain and snow even during the coldest months. This characteristic of the climate normally holds snow depth on the ground to below what it would be without mild periods and rainfall occurring. Canaan Valley's elevation and geographic location allow it to receive significant upslope snow (Orographic lift) regularly during the winter, particularly during prolonged periods of northwesterly winds coming off of the Great Lakes. Such synoptic situations can generate prolonged blizzard conditions. Located along the spine of the Central Appalachian Mountains, the Valley is often near the western edge of Nor'easters, occasionally getting blizzards from strong, Atlantic moisture-laiden, easterly winds. History Prehistory and settlement Canaan Valley and surrounding areas were strongly impacted by the southward advance of glaciers some 15,000 years ago. Although the glaciers themselves did not extend this far south into the area, this climatic change resulted in a very cool, moist environment that was forest-unfriendly. Later, as the ice receded, many cold-adapted plant species remained behind and survived due to the high elevation. Soon, however, this tundra-like vegetation was largely