Hazardous Weather - ATC Vocabulary Flashcards

Vocabulary flashcards covering key hazardous weather concepts and terms from the ATC lecture notes.

Aviation weather hazard

An atmospheric condition encountered in flight that can cause damage, injury, or death; risk depends on pilot and aircraft capabilities.

Adverse weather

Weather hazards and conditions that negatively affect flight operations.

Adverse wind

Winds that cause hazardous effects, especially during takeoff and landing; includes crosswinds, gusts, tailwinds, and wind shifts.

Crosswind

A wind not parallel to the runway; can cause drift during takeoff/landing and requires pilot compensation.

Tailwind

A wind component from behind the aircraft; increases ground speed and can lengthen takeoff or hinder landing.

Variable wind

Wind that changes direction frequently; defined by criteria on directional change and speed.

Wind shift

A change in wind direction of 45 degrees or more in less than 15 minutes with sustained winds of 10+ knots.

IFR weather

Weather conditions that require instrument flight rules; below VFR minimums; vertigo and unseen obstacles risk.

Ceiling

The lowest layer aloft reported as broken/overcast or vertical visibility into an indefinite ceiling.

Layer Aloft Ceiling

The lowest ceiling layer aloft that is broken or overcast (e.g., BKN005).

Indefinite Ceiling

Ceiling classification where vertical visibility is upward into a surface-based obscuration; more hazardous.

Fog

Visible aggregation of water droplets at the Earth’s surface reducing visibility; forms when temperature equals dew point.

Precipitation

Forms of water that fall from the atmosphere to the ground (rain, drizzle, snow).

Blowing snow

Snow lifted by wind to 6 feet or more above ground, reducing visibility to less than 7 statute miles.

Mountain obscuration

Conditions over mountains where pilots should not expect to maintain visual meteorological conditions or see mountains near the route.

Volcanic ash cloud

Fine volcanic ash suspended in the atmosphere; may not be radar-detectable; can cause engine damage and IFR conditions.

Rime ice

Rime ice formed by small supercooled droplets; rough, milky, opaque; common and easiest to remove.

Clear ice (glaze)

Glossy ice from large droplets; more hazardous; disrupts airflow and can be hard to remove.

Mixed ice

Ice that shows both rime and clear characteristics; appears in layers; difficult to identify visually.

Icing intensity TRACE

Ice becomes perceptible with slow accumulation; deicing/anti-icing used only if exposure is extended.

Icing intensity Light

Ice accumulation that may cause problems if flight is prolonged; deicing/anti-icing used as needed.

Icing intensity Moderate

Moderate accumulation; can be hazardous; deicing or diversion typically required.

Icing intensity Severe

Severe accumulation; deicing may not control the hazard; immediate diversion necessary.

Supercooled water

Liquid water below 0°C that freezes upon contact with aircraft surfaces, contributing to icing.

Structural icing

Ice that sticks to the exterior surfaces; includes rime, clear, and mixed types.

Downburst

A strong downdraft causing damaging winds on or near the ground; can be straight or curved.

Microburst

A small downburst with outflow ≤ 2.5 miles, potentially up to 150 knots; highly hazardous to takeoff/landing.

Macroburst

A convective downdraft with outflow area > 2.5 miles; winds 5–20 minutes; possible tornado-like damage.

Turbulence

Irregular aircraft motion due to atmospheric wind variations; ranges from light to extreme; may cause structural damage.

Convective turbulence

Turbulence produced by convective storms with strong updrafts and downdrafts.

Mechanical turbulence

Turbulence caused by obstructions disrupting wind flow (trees, buildings, mountains).

Wind shear

Change in wind speed and/or direction over a short distance, causing tearing or a shearing effect.

Low-level wind shear (LLWS)

Wind shear below 2,000 ft AGL (not convectively induced) exceeding 10 knots per 100 ft; dangerous during takeoff/landing.

Inversion

A layer where temperature increases with altitude, contributing to wind shear; common at night, in valleys, or near fronts.

Frontal zone

Interface between two air masses of different density; can produce strong winds even without clouds.

Clear Air Turbulence (CAT)

Turbulence at high altitude in clear air, associated with wind shear near jet streams; best avoided by altitude change.

Jet stream

A fast-moving air current in the upper atmosphere; related to CAT and high-altitude wind patterns.

Mountain waves

Atmospheric gravity waves formed when stable air flows over mountains; can cause severe turbulence and extend downwind.

Density altitude

Pressure altitude adjusted for nonstandard temperature; high density altitude reduces power and thrust, increasing takeoff/landing distance.

High density altitude

Condition where air density is low and performance is reduced; longer takeoff/landing rolls and lower aircraft performance.