<P> The most well - known winter effect of the Great Lakes on regional weather is the lake effect in snowfall, which is sometimes very localized . Even late in winter, the lakes often have no icepack in the middle . The prevailing winds from the west pick up the air and moisture from the lake surface, which is slightly warmer in relation to the cold surface winds above . As the slightly warmer, moist air passes over the colder land surface, the moisture often produces concentrated, heavy snowfall that sets up in bands or "streamers". This is similar to the effect of warmer air dropping snow as it passes over mountain ranges . During freezing weather with high winds, the "snow belts" receive regular snow fall from this localized weather pattern, especially along the eastern shores of the lakes . Snow belts are found in Wisconsin, Michigan, Ohio, Pennsylvania, and New York, United States; and Ontario, Canada . </P> <P> The lakes also moderate seasonal temperatures to some degree, but not with as large an influence as do large oceans; they absorb heat and cool the air in summer, then slowly radiate that heat in autumn . They protect against frost during transitional weather, and keep the summertime temperatures cooler than further inland . This effect can be very localized and overridden by offshore wind patterns . This temperature buffering produces areas known as "fruit belts", where fruit can be produced that is typically grown much farther south . For instance, Western Michigan has apple and cherry orchards, and vineyards cultivated adjacent to the lake shore as far north as the Grand Traverse Bay and Nottawasaga Bay in central Ontario . The eastern shore of Lake Michigan and the southern shore of Lake Erie have many successful wineries because of the moderating effect, as does the Niagara Peninsula between Lake Erie and Lake Ontario . A similar phenomenon allows wineries to flourish in the Finger Lakes region of New York, as well as in Prince Edward County, Ontario on Lake Ontario's northeast shore . Related to the lake effect is the regular occurrence of fog over medium - sized areas, particularly along the shorelines of the lakes . This is most noticeable along Lake Superior's shores . </P> <P> The Great Lakes have been observed to help intensify storms, such as Hurricane Hazel in 1954, and the 2011 Goderich, Ontario tornado, which moved onshore as a tornadic waterspout . In 1996 a rare tropical or subtropical storm was observed forming in Lake Huron, dubbed the 1996 Lake Huron cyclone . Rather large severe thunderstorms covering wide areas are well known in the Great Lakes during mid-summer; these Mesoscale convective complexs or MCCs can cause damage to wide swaths of forest and shatter glass in city buildings . These storms mainly occur during the night, and the systems sometimes have small embedded tornadoes, but more often straight - line winds accompanied by intense lightning . </P> <P> Historically, the Great Lakes, in addition to their lake ecology, were surrounded by various forest ecoregions (except in a relatively small area of southeast Lake Michigan where savanna or prairie occasionally intruded). Logging, urbanization, and agriculture uses have changed that relationship . In the early 21st century, Lake Superior's shores are 91% forested, Lake Huron 68%, Lake Ontario 49%, Lake Michigan 41%, and Lake Erie, where logging and urbanization has been most extensive, 21% . Some of these forests are second or third growth (i.e. they have been logged before, changing their composition). At least 13 wildlife species are documented as becoming extinct since the arrival of Europeans, and many more are threatened or endangered . Meanwhile, exotic and invasive species have also been introduced . </P>

How many gallons of water are in each of the great lakes