A twin-tip ski is turned up at both the tip and the tail, rather than just the front, so the skier can take off, land, and ski backward (switch) as easily as forward. Twin-tips are the standard for freestyle skiing in terrain parks and pipes, enabling spins and switch landings, and the upturned tail also helps in powder and variable snow.
Frame bindings are alpine touring bindings in which the toe and heel pieces are joined by a rigid frame that pivots at the toe for climbing and locks down for descents. Their big advantage is accepting standard alpine boots and feeling familiar and stable on the descent, but they're significantly heavier than tech bindings, since the whole frame lifts with each step.
Tech bindings (pin bindings) are lightweight alpine touring bindings that hold the boot with metal pins clipping into dedicated inserts in the boot's toe and heel, requiring tech-compatible boots. The pivoting toe makes climbing very efficient, and their low weight makes them the standard for serious ski touring and ski mountaineering, trading some downhill stability and easy release versus frame bindings.
Sun cups are bowl- or cup-shaped hollows that form in a snow surface from uneven melting under strong sun, creating a honeycomb-like dimpled texture. Common on spring and summer snowfields and at altitude, they range from small dimples to deep, awkward depressions that make walking and skiing tiring and uneven. They're a fair-weather snow feature, not an avalanche concern.
Firn is old, dense, granular snow that has survived at least one melt season and been compacted, representing the intermediate stage between fresh snow and glacier ice. Found in glacier accumulation zones and on permanent snowfields, firn is denser than seasonal snow but not yet solid ice, and is part of how glaciers form over years of compaction.
Graupel is soft, round, white snow pellets that form when supercooled water droplets freeze onto a falling snowflake (a process called riming), creating little ball-bearing-like grains. It can pile up on the snow surface and, when buried, act like ball bearings as a weak layer that contributes to avalanche danger, so it's of interest to backcountry travelers.
Sastrugi are sharp, irregular ridges and grooves carved into a snow surface by strong, persistent wind, common on exposed alpine slopes, ridgelines, and polar plains. Firm and uneven, they make for rough, jarring skiing and walking and signal significant wind effect on the snow surface — a clue to wind loading and possible wind slabs nearby.
Après-ski (French for 'after ski') is the social tradition of relaxing with food, drinks, music, and company after a day on the slopes, typically at bars, lodges, and restaurants at or near the resort. A beloved part of ski culture — especially in the Alps — it ranges from a quiet hot drink by the fire to lively parties, and is for many an essential part of the ski experience.
First tracks means being the first to ski or ride a slope of fresh, untracked snow, laying down the first lines before anyone else. Prized after a powder snowfall for the pristine, smooth, floating experience, chasing first tracks drives early-morning lift lines and dawn backcountry starts. Some resorts even sell early 'first tracks' access.
A halfpipe is a U-shaped channel carved and groomed into the snow, with walls that riders use to gain air and perform aerial tricks as they travel down its length. A staple of competitive freestyle skiing and snowboarding (and an Olympic event), the modern 'superpipe' has walls up to around 22 feet high. Riding it demands strong fundamentals, including riding switch.