About half of Minnesota is covered by the rolling plains left by the last ice age. These areas are covered by fertile topsoil and this area has some of the richest farmland in the United States. Along the Mississippi River, in the southeastern section of the state, the land is flat, cut by deep valleys created by fast flowing rivers and streams. In the far northeast, the border resembles an arrowhead. This area is called the Arrowhead Country; this area is more rugged and includes the Vermilion Range and the Mesabi Range, which has rich iron deposits. Eagle Mountain, in the far northeast, rises to a height of 2,301ft (702m), the highest point in the state; the surface of nearby Lake Superior, 600ft (183m) above sea level, is the state's lowest point.
Most of Minnesota, except for small areas in the southeast, was covered by ice during the last ice age. When the ice melted, it left behind a body of water known as Lake Agassiz, which was larger than all of the Great Lakes combined. When the lake drained away, it left flat prairie. The glaciers also left behind large stretches of finely ground minerals, which enriched Minnesota's soil, and many shallow depressions that have turned into today's many lakes and streams.
With more than 15,000 lakes and extensive wetlands, rivers, and streams, Minnesota has more inland water than any other state except Alaska. Some of the inland lakes are quite large, such as: Lower and Upper Red Lake, 451 sq mi (1,168 sq km); Mille Lacs, 207 sq mi (536 sq km); and Leech Lake, 176 sq mi (456 sq km). The Lake of the Woods, 1,485 sq mi (3,846 sq km), is shared with Canada, as is Rainy Lake, 345 sq mi (894 sq km). A large amount of Lake Superior also lies within Minnesota.
Lake Itasca, in the northwest, is the source of the Mississippi River. The Minnesota River, which flows across the southern part of the state, joins the Mississippi at the Twin Cities. The Red River of the North forms much of the boundary with North Dakota, and eventually empties into Lake Winnipeg in Canada. The Red River Valley is a plain which was created when the ancient Lake Agassiz dried up. Red Lake, Lake of the Woods, and Canada’s Lake Winnipeg are all remnants of this huge body of glacial meltwater.
The far southeast of Minnesota was the only part of the state which was not covered by glaciers during the last ice age. There, streams cut their way through layers of limestone, leaving extensive caverns beneath the surface and steep, rocky bluffs rising high above the valleys.
Minnesota has a continental climate, with cold, often frigid winters and warm summers. Temperatures vary from one part of the state to another. Southern Minnesota is hot in the summer, while in the northern regions of the state, frost is possible in any month.
Average daily maximum temperatures in July range from the mid-80s F (about 29°C) in southern Minnesota to the low 70s F (about 21°C) along the shore of Lake Superior. Average daily January highs range from the mid-20s F (about -4°C) in the south to about 15°F (-9°C) in the north. Record-breaking lows have been known to occur; in 1996 a temperature of -60°F (-51°C) was recorded near the northeastern city of Tower.
Average seasonal snowfall varies from less than 40in (1,000mm) in the western part of the state to more than 70in (1,800mm) in the northeastern tip. Many parts of Minnesota have continuous snow cover for at least 90 days, from about mid-December to mid-March. The lowest temperature recorded in Minnesota was –60°F (–51°C), at Tower on 2 February 1996; the highest, 114°F (46°C), at Moorhead on 6 July 1936.
Blizzards hit Minnesota twice each winter on the average. Tornadoes occur mostly in the south, with around 18 tornadoes striking the state each year.
