Microbursts, Chinook Winds, Cloud Formation

1. Microbursts, Chinook Winds, Cloud Formation Vapor and Energy in the Atmosphere

2. Context • Structure of the atmosphere • Issues: ozone, global warming, acid rain • Basic weather concepts • Temperature, humidity, dew point, cloud formation, fronts, pressure, highs and lows • Storms • Thunderstorms, mid-latitude cyclones, hurricanes • climate About 10 weeks

3. Purpose • Cloud formation demos • Cloud formation activity • Energy demo • Lab activity that will help your students better understand . . . • Microbursts • Chinook Winds • Hurricanes

4. Cloud Demos (3) • Watch a video of the “ultimate” cloud demo • Click here NEXT: The student activity

5. Do NOT try this at home DEMO how alcohol vapors burn.

6. Student ActivityWhat’s the recipe for a cloud? • Click here to watch a video of the student activity. NEXT: Energy Demo

7. If you understand this, you can understand the Chinook effect. Show psychrometer

8. Take a look at the handout. Water Vapor Water molecules releaseheat. Water molecules absorbheat. B D A Liquid Water F Surrounding air gets warmer. Surrounding air gets colder. C E Frozen Water (Ice)

9. NEXT: Questions to be answered after the experiment.

11. 0 C * - 4 C ICE SLUSH

12. Chinooks are common in rain shadows There’s more to it than just compression.

13. Examples of The Chinook Effect • In January of 1916, Browning had a temperature swing of 100 F • At Havre a temperature increase of 43 F in 15 minutes has been recorded. • At Loma on January 15, 1972 temp. increased from -56 F to 49 F

14. Look at question #4 on the handout.

15. What is the area inside yellow line called?Why are Chinooks most common in this area?

16. NEXT

18. Not just a Montanaphenomenon • Rapid City 1943 • 7:30 am temp was -4 F • In 2 minutes it rose 49 degrees • 9:00 am temp was 54 F • By 9:30 am temp was -4 F again

21. Chinook does not mean “Snow Eater” . . . But they do “eat” snow

22. Next: MicroburstsQuestion #6 Small intense downburst

23. 1920-1998 Saw destruction at Hiroshima and Nagasaki Moved to USA in 1953 Tornado outbreak of April 1974 Eastern Airlines flight #66 in 1975 Downbursts: Discovered by Ted Fujita

24. Dr. Greg Forbes Fujita’s most famous student

25. “Tornado Outbreak” April 3-4, 1974 • 148 twisters • 16 hours • 330 deaths • Six F-5s • Several ???

26. Downed trees provide evidence. Photo courtesy of T. Fujita Shows damage from 1977 downburst in Northern Wisconsin

27. Photo courtesy of T. Fujita Swath was 166 miles long, 17 miles wide

28. Watch a short video-demonstration. Downbursts

31. July 14, 2005 9 p.m.

35. Question #7

36. #8 Psychrometer

37. #9. Warm Water is the “fuel” • Vapor from warm water enters storm • Humid air rises -> cools by expansion • Vapor changes to liquid cloud droplet • Heat energy released • Makes air lighter -> helps it rise • Pressure becomes lower • Wind speed toward storm center increases

38. Questions 10-15 Water Vapor Water molecules releaseheat. Water molecules absorbheat. B D A Liquid Water F Surrounding air gets warmer. Surrounding air gets colder. C E Frozen Water (Ice)

39. Resources • This presentation is available on www.TeacherTube.com • rbenson@helena.k12.mt.us • Rodney’s Homepage for Earth Science Teachers • www.formontana.net/home.html If time allows . . . Chinook Arch