The Intermountain West, or Intermountain Region, is a geographic and geological region of the Western United States. It is located between the front ranges of the Rocky Mountains on the east and the Cascade Range and Sierra Nevada on the west. Topography The Intermountain West has a basin and range and plateau topography. Some of the region's rivers reach the Pacific Ocean, such as the Columbia River and Colorado River. Other regional rivers and streams are in endorheic basins and cannot reach the sea, such as the Walker River and Owens River. These flow into brackish or seasonally dry lakes or desert sinks. Portions of this region include: Basin and Range Province Colorado Plateau Great Basin Intermontane Plateaus Climate The climate of the Intermountain Region is affected by location and elevation. The sub-regions are in rain shadows from the Cascade or Sierra Nevada ranges that block precipitation from Pacific storms. The winter weather depends on latitude. In the southern portion, winters are shorter, warmer and have less winter precipitation and snow. In the northern portion, winters are cold and moist. All areas have hot summers. North American Monsoon storms can occur in the region during the mid-summer, coming northeast from the Pacific Ocean and Mexican Plateau. Natural history The flora at lower elevations includes deserts and xeric shrublands and temperate grasslands and shrublands biome vegetation. Higher elevation montane habitats include temperate coniferous forests biome vegetation, including groves and forests of various species of pine, cedar, juniper, aspen, and other trees, and understory shrubs, and perennials. Intermountain West ecoregions include: Central Basin and Range ecoregion – North American Deserts; Level III ecoregion (EPA) Columbia Plateau (ecoregion) – Temperate grasslands, savannas, and shrublands biome (WWF) Eastern Cascades Slopes and Foothills (ecoregion) – Northwestern Forested Mountains; Level III ecoregion (EPA) Great Basin shrub steppe – Deserts and xeric shrublands biome (WWF) Great Basin montane forests – Temperate coniferous forest biome (WWF) Northern Basin and Range ecoregion – North American Deserts; Level III ecoregion (EPA) Palouse grasslands ecoregion – Temperate grasslands, savannas, and shrublands biome (WWF) Snake River Plain (ecoregion) – North American Deserts; Level III ecoregion (EPA) Wasatch and Uinta montane forests ecoregion – Temperate coniferous forest biome (WWF) Some sections are agriculturally cultivated with water diversions for irrigation systems. Cattle ranching is practiced in the region as well. Cultivated crops include corn, potatoes, sugar beets, grass hay, and alfalfa, the latter two