Field Guide / Clouds & Weather Signs
Lenticular Clouds
flying saucer clouds
Smooth, lens-shaped clouds that sit still near mountains. They mark strong winds aloft and rough air, and they often come before a change in the weather.
- Height
- Special & Ground-Level
- Abbreviation
- Ac len
- Typical altitude
- About 6,500–20,000 ft (2,000–6,000 m)
- Usually means
- Weather changing
How to recognize it
- Smooth, lens-shaped or saucer-shaped clouds, sometimes stacked like pancakes.
- They stay in place even when the wind is strong.
- Often form on the downwind side of a mountain range.
What it usually means
- Strong winds aloft, often with powerful gusts on exposed summits and ridges.
- Weather often changes within a day, so lenticular clouds can come before storms.
- Lenticular clouds are a sign of rough air for aircraft.
What to do outdoors
- Stay off exposed ridges and summits when lenticular clouds are overhead, since wind can be dangerous.
- Check the mountain forecast and be ready to turn around.
Often confused with
- Altocumulus: lumpy rolls that drift, instead of smooth lens shapes that stay in place.
Field notes
Lenticular clouds form when air flows up and down in waves behind a mountain. The cloud forms at the crest of each wave and dissolves at the bottom, so it seems to stay put even when the wind is blowing hard.
Related guides
Cloud signs are rough guides, not forecasts. Always check the National Weather Service forecast at weather.gov before and during a trip, carry a way to receive alerts, and treat any watch or warning as a reason to change your plans. If you can hear thunder, you are close enough to be struck by lightning.