Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water...
Transcript of Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water...
![Page 1: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/1.jpg)
Part 2 Dangerous areas on glaciers
Photo: K. Bælum
![Page 2: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/2.jpg)
Dangerous areas on glaciers
• Crevasses (cracks in the surface)
![Page 3: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/3.jpg)
Photo: Wikipedia
![Page 4: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/4.jpg)
ICEICE
Where and why do crevasses form?
Illustration: K. Bælum
![Page 5: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/5.jpg)
Compression = deformation (some times fractures)
Illustration: K. Bælum
![Page 6: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/6.jpg)
Illustration: K. Bælum
![Page 7: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/7.jpg)
Illustration: K. Bælum
![Page 8: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/8.jpg)
Extension = Fractures
Illustration: K. Bælum
![Page 9: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/9.jpg)
Illustration: K. Bælum
![Page 10: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/10.jpg)
Photo: K. Bælum
![Page 11: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/11.jpg)
Shear = fractures
Illustration: K. Bælum
![Page 12: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/12.jpg)
Illustration: K. Bælum
![Page 13: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/13.jpg)
Photo: K. Bælum
![Page 14: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/14.jpg)
Uplift = fractures
Illustration: K. Bælum
![Page 15: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/15.jpg)
Illustration: K. Bælum
![Page 16: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/16.jpg)
Photo: K. Bælum
![Page 17: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/17.jpg)
Dangerous areas on glaciers
• Crevasses (cracks in the surface)• Melt water channels
– Most glaciers have melt water channels, some have many, some few
– They may not always be covered with sufficient snow – especially not in early winter
– They can be 10-20m deep.
![Page 18: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/18.jpg)
Melt water channels in late autumn
![Page 19: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/19.jpg)
Melt water channels
A recent melt water channel accident fortunately ended well
![Page 20: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/20.jpg)
Dangerous areas on glaciers
• Crevasses (cracks in the surface)• Melt water channels• Moulins (glacier wells, big holes in the glacier
surface)
![Page 21: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/21.jpg)
Dangerous areas on glaciers
![Page 22: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/22.jpg)
Photo: M. Sund
10 m
Waterfall
![Page 23: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/23.jpg)
Dangerous areas on glaciers• Crevasses (cracks in the surface)• Melt water channels• Moulins (glacier wells, big holes in the glacier
surface)• Melt water/ Icings in front of the glacier, summer
and winter– Found in front of glaciers
– They can occur even at very low temperatures
– Some of the water may be frozen, but liquid water may also be covered by snow or a thin ice layer.
![Page 24: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/24.jpg)
Photo: M. Sund
![Page 25: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/25.jpg)
Don't park your scooter overnight in front of a glacier!
Photo: R. Behlke
![Page 26: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/26.jpg)
Dangerous areas on glaciers
• Crevasses (cracks in the surface)• Melt water channels• Moulins (glacier wells, big holes in the glacier
surface)• Melt water in front of the glacier, summer and
winter• Steep mountain sides around the glacier, falling
rocks and avalanches
![Page 27: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/27.jpg)
Outside of turn,Marginal crevasses
Inside of turn,compaction
Steep section, icefall,Extensional crevasses
Front and sides of glacier,marginal crevasses
Widening of the cross profile.Extensional crevasses along flow lines
Narrowing of the cross profile,transversal crevasses
Dome on the bed rock, uplift.
Chaotic crevasse pattern
Below mountainside,Bergschrund.
Along sides, and on the glacierMelt water channels.
Melt water/icing at the front, even in winter.
Moulins (glacier wells)
![Page 28: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/28.jpg)
Ice flows downhill.
Illustration: K. Bælum
![Page 29: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/29.jpg)
600m
500m
400m
300m
Illustration: K. Bælum
90°
General rule - Ice flows downhill, perpendicular to the contour lines
![Page 30: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/30.jpg)
![Page 31: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/31.jpg)
Some of the problem areas can be identified from a map
![Page 32: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/32.jpg)
Extensional stress
Bergscrund and meltwater channels
Lakes on the surface
Transverse stress
Uplift areas
Front of glacier
![Page 33: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/33.jpg)
Extensional stress
Bergscrund and meltwaterchannels
Lakes on the surface
Transverse stress
Uplift areas
Front of glacier
Remember: This is just a map not the real thing!
![Page 34: Part 2 Dangereous areas on glaciers€¦ · • Crevasses (cracks in the surface) • Melt water channels – Most glaciers have melt water channels, some have many, some few –](https://reader033.fdocuments.net/reader033/viewer/2022060608/605ff31fb65d120fb764abb1/html5/thumbnails/34.jpg)
IMPORTANT: Svalbard maps are partly based on old aerial photos – the glaciers could have change a lot
during this time (e.g. surges) !
The newest maps available still have 13 to 18 years old glacier data