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Secrets of the St. Lawrence
Extra - Beaufort
Extra (PDF; 62 KB)
| Force | Wind Speed | Descriptive Term | Effects Observed at Sea | Effects Observed on Land | |
|---|---|---|---|---|---|
| Km/h | Knots | ||||
| 0 | Less than 1 | Less than 1 | Calm | Sea surface like a mirror, but not necessarily flat. | Smoke rises vertically. |
| 1 | 1 - 5 | 1 - 3 | Light air | Ripples with the appearance of scales are formed, but without foam crests. | Direction of wind shown by smoke drift, but not wind vanes. |
| 2 | 6 - 11 | 4 - 6 | Light breeze | Small wavelets, still short but more pronounced. Crests do not break. When visibility good, horizon line always very clear. | Wind felt on face. Leaves rustle. Ordinary vane moved by wind. |
| 3 | 12 - 19 | 7 - 10 | Gentle breeze | Large wavelets. Crests begin to break. Foam of glassy appearance. Perhaps scattered whitecaps. | Leaves and small twigs in constant motion. Wind extends light flag. |
| 4 | 20 - 28 | 11 - 16 | Moderate breeze | Small waves, becoming longer. Fairly frequent whitecaps. | Raises dust and loose paper. Small branches are moved. |
| 5 | 29 - 38 | 17 - 21 | Fresh breeze | Moderate waves, taking a more pronounced long form. Many whitecaps are formed. Chance of some spray. | Small trees with leaves begin to sway. Crested wavelets form on inland waters. |
| 6 | 39 - 49 | 22 - 27 | Strong breeze | Large waves begin to form. The white foam crests are more extensive everywhere. Probably some spray. | Large branches in motion. Whisteling heard in telephone wires. Umbrellas used with difficulty. |
| 7 | 50 - 61 | 28 - 33 | Near gale | Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind. | Whole trees in motion. Inconvenience felt in walking against wind. |
| 8 | 62 - 74 | 34 - 40 | Gale | Moderately high waves of greater length. Edges of crests begin to break into the spindrift. The foam is blown in well-marked streaks along the direction of the wind. | Breaks twigs off trees. Generally impedes progress. Walking into wind almost impossible. |
| 9 | 75 - 88 | 41 - 47 | Strong gale | High waves. Dense streaks of foam along the direction of the wind. Crests of waves begin to topple, tumble and roll over. Spray may affect visibility. | Slight structural damage occurs, e.g. roofing shingles may become loose or blow off. |
| 10 | 89 - 102 | 48 - 55 | Storm | Very high waves with long overhanging crests. Dense white streaks of foam. Surface of the sea takes a white appearance. The tumbling of the sea becomes heavy and shock-like. Visibility affected. | Trees uprooted. Considerable structural damage occurs. |
| 11 | 103 - 117 | 56 - 63 | Violent storm | Exceptionally high waves. Sea completely covered with long white patches of foam. Visibility affected. | Widespread damage. |
| 12 | 118 - 133 | 64 - 71 | Hurricane | Air filled with foam and spray. Sea entirely white with foam. Visibility seriously impaired. | Rare. |
- 1. Fore to aft
- 2. What Cartier missed out on
- 3. Conversion
- 4. The Secrets of the St Lawrence
- 5. The wind in your sails - Hard a-port!
- 6. The wind in your sails - Fast or slow?
- 7. The wind in your sails - The wind's paths
- 8. The wind in your sails - Against the wall
- 9. The wind in your sails - Solar energy
- 10. The wind in your sails - Under the stars
- 11. The wind and the waves - The windway
- 12. The wind and the waves - Wave wars
- 13. The wind and the waves - Graveyards
- 14. The wind and the waves - Conflicting seas
- 15. Symbols
- 16. The St Lawrence, from 1 to... - Legend
- 17. The St Lawrence, from 1 to... - Calling all sailors
- 18. The St Lawrence, from 1 to... Hot spots
- 19. Local listings - Québec - Pointe-des-Monts
- 20. Local listings - Pointe-des-Monts - Cap Whittle
- 21. Local listings - Cap Whittle - Blanc-Sablon
- 22. Local listings - Gaspésie - Baie des Chaleurs
- 23. Local listings - Îles de la Madeleine
- 24. Sailors take warning - White-outs
- 25. Sailors take warning - The sky above us
- 26. Sailors take warning - Keeping a weather eye
- 27. Sailors take warning - Fair weather and foul
- 28. Sailors take warning - The unexpected
- 29. The four seasons - Wind aplenty
- 30. The four seasons - Vessel icing
- 31. The four seasons - Ice cycle
- 32. Extra - Beaufort
- 33. Extra - Handy references
- 34. Extra - Old Salts and Sea-dogs
- 35. Extra - The crew
- 36. Extra - A to Z
- 37. Extra - Stations
- 38. Extra - Areas
- 39. Credits
- Date modified: