A pilot's preflight weather briefing includes an active AIRMET Sierra covering the route of flight. What hazard does this AIRMET specifically address?
- AModerate icing and freezing levels
- BSevere thunderstorms with tornadoes and hail
- CWidespread IFR conditions and/or extensive mountain obscuration
- DModerate turbulence and sustained surface winds of 30 knots or greater
Show answer & explanationAnswer & explanation
Correct answer: C. Widespread IFR conditions and/or extensive mountain obscuration
AIRMET Sierra (IFR/Mountain Obscuration) warns of widespread instrument flight rules conditions, ceilings below 1,000 feet and/or visibility below 3 statute miles affecting at least 50% of the area, or extensive mountain obscuration by clouds, precipitation, or dust. AIRMET Tango covers turbulence and strong winds, AIRMET Zulu covers icing, and Convective SIGMETs cover severe thunderstorms.
Why the other options are wrong
- A. Icing hazards are covered by AIRMET Zulu, not Sierra.
- B. Severe thunderstorm activity is covered by Convective SIGMETs, not AIRMET Sierra.
- D. This describes AIRMET Tango, not Sierra.
AIRMET Sierra
AIRMET Sierra warns of widespread IFR conditions (ceilings below 1,000 feet and/or visibility below 3 statute miles) and/or extensive mountain obscuration, affecting a significant portion of the forecast area.
- Sierra = IFR conditions/mountain obscuration
- Tango = turbulence and sustained surface winds ≥30 knots
- Zulu = icing and freezing levels
Memory trick: 'Sierra Sees poor Sight' — Sierra covers IFR/mountain obscuration.