1. Northwest Cloud formations Northwest Cloud formations Geology 252: The Earth and its Weather Ron Kleinknecht

2. High Clouds (Cirrus) C H Etymology : Latin, Tendril, flexible appendage Height: Above 10,000 ft. (3 km) to ~ 60,000 ft. (18 km). Tropopause Ice crystals Forms: –mares tails, hooks, filaments & strands –cirrofractus –cirrostratus –cirrocumulus (mackerel sky)

3. Mares’ tails over Whistler

4. Cirrus with strands, filaments and hooks

5. Cirrus with more strands and filaments

6. Cirrus (Stratus?)

7. Sun Dog (parahelia) Through Cirrostratus

8. Sundog in Perspective

9. Cirrocumulus (Mackerel Sky)

10. Cirrus and Stratus at Sunset

11. Alto, (high) mid- level clouds (Cm) Height: Between 6,500 ft. (2 km) and 25,000 ft. (8 km) Forms: –Altocumulus –Altostratus

12. Altocumulus

13. Altostratus and Cumulus Congestus over Orcas Island

14. Winter Altostratus over South Bellingham

15. Layers of Cirrus, Altostratus and ?

16. Low Clouds (C L ) Height: ground to 6,500 ft. (2 km) Forms: –Fog –cumulus –stratus –Nimbostratus (rain) –cumulonimbus (rain/storm) Base starts low but can develop up to tropopause

17. October Cumulus with Moderate Vertical Development

18. Dissipating Cumulonimbus

19. Summer Stratocumulus July 2001

20. Late Summer Stratus with Fog Lifting

21. Stratocumulus over the Bay at Summer Sunset July 2001

22. Altocumulus at night: Sailors’ delight or warning?

23. Where is the Virga?

24. Weather Dragons Come Out

25. Looking for the green flash