Dust storms and sandstorms
Dust storm and sandstorm are severe, wind-driven dust or sand in the air. They differ in extent and height.
| Event | Extent |
|---|---|
| Dust storm | Extensive |
| Sandstorm | Localized; sand stays low, heavier than dust (AWH 18.1.8) |
Present weather codes (TC AIM MET 8.2, Table 8.1):
| Code | Meaning | Visibility |
|---|---|---|
DU |
Dust present in air | No threshold |
SA |
Sand present in air | No threshold |
DS |
Dust storm | Under 5/8 SM |
SS |
Sandstorm | Under 5/8 SM |
+DS |
Dust storm, tighter band | Under 5/16 SM |
+SS |
Sandstorm, tighter band | Under 5/16 SM |
Dust hazards (AWH 18.1.7):
- Air-to-ground (slant range) visibility generally worse than reported surface horizontal visibility.
- Aerodrome may be invisible from above even at surface visibility of 3 mi or more.
- Visibility in a dust storm can drop to zero within seconds.
- Dust can clog engine air intakes.
Trap: judging a dust storm by the surface report; air-to-ground visibility is generally worse and can reach zero within seconds.
References
- FAA AWH 18.1.7 (dust storm)
- FAA AWH 18.1.8 (sandstorm)
- TC AIM MET 8.2, Table 8.1 (Significant Present Weather Codes)