snow line
Permanent white border
The snow line is the elevation on a mountain above which snow remains year-round, or the latitude beyond which permanent snow cover begins.
The line shifts seasonally and varies by climate: The snow line in the tropics sits around 15,000 feet.
Below the snow line, summer warmth melts accumulated snow; above it, temperatures stay cold enough for snow to persist.
Elevation limit for forests
- altitudeMeasured height above reference
- summitPeak or diplomatic gathering
- peakUtmost height attained
- alpineOf high elevations
subalpine · montane · ridge · timberline · high altitude · mountain climate
Constant-temperature boundary line
- freezing levelHeight where air reaches zero
- permafrostPerpetually frozen earth layer
- arcticOf extreme northern cold
- polarOf extreme latitudes
cryosphere · albedo · seasonal variation · global warming · climate change · snowmelt · precipitation · winter
Slow-moving ice mass
- firnYear-old compacting snow
- névéGranular, compacted alpine snow
- accumulation zoneWhere ice sheet grows
- crevasseDeep glacial fissure
moraine · icefield · glacial retreat · serac · icefall · cirque · calving · meltwater
Midpoint circle of rotation
- tropicWarm Earth zone
- latitudeGeographic or personal freedom
- hemisphereHalf of a ball
- mountain rangeSeries of connected peaks
cordillera · continental · regional variation · terrain · topography · aspect · north-facing · south-facing
treeline
Elevation limit for forests
alpine · subalpine · montane · ridge · timberline · high altitude · mountain climate
isotherm
Constant-temperature boundary line
- freezing levelHeight where air reaches zero
- permafrostPerpetually frozen earth layer
- arcticOf extreme northern cold
polar · cryosphere · albedo · seasonal variation · global warming · climate change · snowmelt · precipitation · winter · latitude
glacier
Slow-moving ice mass
- firnYear-old compacting snow
- névéGranular, compacted alpine snow
- accumulation zoneWhere ice sheet grows
crevasse · moraine · icefield · glacial retreat · serac · icefall · cirque · calving · meltwater · glaciology
equator
Midpoint circle of rotation
- tropicWarm Earth zone
- latitudeGeographic or personal freedom
- hemisphereHalf of a ball
mountain range · cordillera · continental · regional variation · terrain · topography · aspect · north-facing · south-facing · windward
- mountain termsAlps, Himalayas, Rockies, Andes, peaks
- mountain terrainpeak, ridge, slope, gorge, pass
- Winter Terrainice field, frozen tundra, glacier, ice sheet, frozen lake
- glaciersglacier, crevasse, glacial movement, moraine, iceberg
- mountaineeringsummit, alpinist, mountaineer, ice axe, ice axes
- hiking experiencesblisters, fatigue, altitude sickness, dehydration, sunburn
snow linesea level
Elevation reference point
valley floor · tropical zone · tree line · timberline · lowlands
snow linetropics
Warm equatorial region
desert · arid zone · hot zone · equatorial region · rainforest floor