The northern and western parts of the province experience higher rainfall and lower evaporation rates caused by cooler summer temperatures.The south and east-central portions are prone to drought-like conditions sometimes persisting for several years, although even these areas can receive heavy precipitation, sometimes resulting in flooding.There are three large lakes, Lake Claire (1,436 km (451 sq mi)), and Lake Athabasca (7,898 square kilometres (3,049 sq mi)) which lies in both Alberta and Saskatchewan.The longest river in the province is the Athabasca River which travels 1,538 km (956 mi) from the Columbia Icefield in the Rocky Mountains to Lake Athabasca.As the fronts between the air masses shift north and south across Alberta, the temperature can change rapidly.Arctic air masses in the winter produce extreme minimum temperatures varying from −54 °C (−65 °F) in northern Alberta to −46 °C (−51 °F) in southern Alberta, although temperatures at these extremes are rare.it is Canada's fourth most populous province and the most populous of Canada's three prairie provinces. It has a predominantly humid continental climate, with stark contrasts over a year; but seasonal temperature average swings are smaller than in areas further east, due to winters being warmed by occasional chinook winds bringing sudden warming.Its area is about 660,000 square kilometres (250,000 sq mi). Alberta is one of three Canadian provinces and territories to border only a single U. Alberta's capital, Edmonton, is near the geographic centre of the province and is the primary supply and service hub for Canada's crude oil, the Athabasca oil sands and other northern resource industries.
The climate is also influenced by the presence of the Rocky Mountains to the southwest, which disrupt the flow of the prevailing westerly winds and cause them to drop most of their moisture on the western slopes of the mountain ranges before reaching the province, casting a rain shadow over much of Alberta.Alberta has a humid continental climate with warm summers and cold winters.The province is open to cold arctic weather systems from the north, which often produce extremely cold conditions in winter.Almost 75% of the province's population lives in the Calgary–Edmonton Corridor.
The land grant policy to the railroads served as a means to populate the province in its early years.
The region, with its proximity to Canada's largest oil fields, has most of western Canada's oil refinery capacity.