nõlvad

Nõlvad are inclined surfaces of the earth's surface, commonly translated as slopes or hill slopes. In Estonian geography, a nõlv is the face of terrain that rises from a lower area, and nõlvad is the plural.

Slopes form through tectonic uplift, weathering, and erosion over time. Their steepness, shape, and stability depend on rock or soil type, moisture, vegetation, and climate. Slopes can be gentle or very steep and may include features such as spurs, gullies, or escarpments.

Gradient is a common measure of slope steepness, expressed as an angle in degrees or as a percentage grade. Gentle slopes are typically low-grade, while steep slopes are associated with higher risk of erosion and landslides. Slope stability depends on soil cohesion, drainage, roots, and underlying geology.

Human activity interacts with nõlvad. Agriculture on slopes often uses terracing or contour planting to reduce runoff. Forest cover protects against eroding; road and railway design passes require cut-and-fill and retaining structures. Urban areas on slopes face landslide risk and infrastructure design challenges.

In Estonia and similar regions, nõlvad are common in hilly landscapes and coastal terraces. Understanding slopes is essential in geography, engineering, and land-use planning.