Hi Doug,

Your selection of permafrost slide markers is really very interesting. Each of these sites warrants further studies. Your photograps would certainly be of interest. Why not add them to this discussion thread.

Your red marked site is very interesting since it shows very recent as well as 50 year old slide scar areas. The relative recent disturbed bare soil is clearly visible on both sides of the creek. Also the adjacent areas on both sides show significant sliding area which appear to have been stabilized and are recovered with vegetation.


I have taken some time to study your red marked site in more detail using air photos from 1950, 1953, 1972 and 1977, as well as Landsat. the image below shows my interpretation . You are right that the pre 1950 slide caused the formation of the little lake upstream. The pre 1950 slide appears to have been a sudden event. The pink arrow shows the slide path, which also blocked the creek flow, and created a small lake upstream. The the water erosion from the displaced creek started to undermine the north facing slope which showed a steady regression for the next 27 years before stabilizing. Just before the 1990's additional regression occurred on the south facing slope (thin orange line) also occurring as a sudden failure. The new slide areas (yellow dotted line) developed between 1990 and 2000.



Retrogressive Slide on 1950 and 1953 Aerial Photos
The 1950 photo ( A12847-144) was taken on August 2nd, 1950 at a height of 20'000 ft. Original scale 1:40'000. The pink arrow shows the flow direction. The slide, on the south facing slope occurred as a sudden event blocking the flow of the creek and creating a small lake upstream. The drainage channel was pushed into the opposite slope which started to collapse. Both sides continued to melt, but most of the regression in the following decade is in the north facing slope. The 1953 airphoto (A13753-22) was taken on 27 July from 35'000 ft.


1972 and 1977 Air photos
During the next 20 years the North facing slide is regressing. The 1972 and 1977 air photos show that the creek is pushed back again (yellow marker). In this 5 year period the North slide appears stable, and some further sliding occurred on the south facing slide (from blue dotted line to the light blue-grey dotted line). There are no signs of fire scars in the vegetation on these photos, but a fire scars ( (dated between 1958-1978) were identified in close to the Salter Hill area, about 5 km distance from this slide area. 1972 Airphoto (A22972-119) taken on 11 July, from 35'000 ft; 1977 air photo (A24761-133) taken on August 1, from 35'000 ft.



NASA Landsat Pseudo Colour 1990 (left) and 2000 (right). The pink arrow on the 1990 satellite image shows that the south facing slope has become active again. Also the light blue arrow shows the start of the next phase on the north slope. The 1950 and 1970 slide areas still look reasonably stable and are covered with vegetation again. The red arrow on the 2000 image shows a part of the 1950 slide which has become active again: the small dark black area- a mudflow The yellow arrow on the 2000 image points to the dark purple active slide area essentially very similar to the Google Earth image (2007). No fire scars are visible on each of the images.


Fire History for the Yukon 1946-2004 . The map below depicts the wildland fires since 1946. Source: Source: Yukon Energy, Mines and Resources . The Caribou River area described here is marked with the red marker near (1). The closest fires on this map was (3) which occurred between 1990 and 1999. The Trevor Range Site (green marker) is identified with a (2). It will be interesting to study the blue markers provided by kningpointnorth in relation to fire history. A cursory review of some of the sites in recent and older burn areas seems to imply a link with the fires. Legend: Grey= 2000-2004; Red=1990-1999: Pink=1980-1989; Green= 1970-1979; Orange= 1960-1969; Yellow=1950-1959; Light Green= 1946-1949 (not on this part of the map)



Doug, you could add the fire map as overlay to your collection of markers. As you already can see, many of your markers are in burned and non-burned areas. I have looked at a number of the sites in recent burn areas, where the fires appear to be the cause of the slide. Fires can also have an impact on (increased stream flow) and therefore increased erosion.

Fires are already so abundant in this part of the world. If they double in frequency retrogresive thaw slides would certainly become more abundant. It would be interesting to study this with your markers and the existing fire history,

Cheers,

Jean

Hello Jean

Thankyou for doing such an excellent job on analysing the progression of this thaw. It is amazing that it has been active that long (since 1950). I wanted to let you kow that I have not forgotten about posting the pictures I have of other sites from 2005 and 2006. I have finally located the photos and hope to be able to assemble them for you in the coming week. Take Care. Doug

Sounds good Doug,
It would be interesting to see actual camera shots of the thaw slide.

I like to work a bit on an interpretation guide for "old" thaws , because that could be an interesting addition to your collection. On high resolution imgages they are quite easy to identify.

If I am corrrect you are a diving specialist. Any interesting perspective on northern lakes form Google Earth, burbot tunnels?

by the way, what is your connection to King Point? I was at the DEW line station there in the mid 80's. My branch (Lands Directorate of EC) was doing an ecological survey - ecoregion, district mapping of the Norther Yukon at that time

Cheers

Jean

Greetings!
It's a very nice and compehensive work indeed! As studying as an engineer of nature-conversation, i'm happy to see people who care about making interpretations about such problems.
I's a rather small area that is included, however, being important in the whole big picture.
Keep on the good work!
G.

Dear Rauka

Thanks for your comments. It is in fact part of understanding the big picture. Doug identified about one hundred locations like this spread out over the Yukon and part of our North West Territories. And I am looking at about 200 sites of melting peat plateaus and palsas across Canada and Nortern Europe and Asia.

By the way, you are from Sopron. Some of Canada's and the wold's leading permafrost experts come from Hungary. My friends and colleagues Charles Tranocai and Steve Zoltai came from Hungary. Charles came with the Foretry Faculty of Sopron to Canada after the revolution in 56. A link to some of their work

http://www.geostrategis.com/p_sensitivity.h

http://www.geostrategis.com/p_links.htm

Thank you very much for the information Jean, it's surprising! It's a small world as they say...
I'm learning at the University where he had been learning too, before emigrating to Canada, and I greatly respect him/them. (And if you allow some personality, they made the right decision going there...)
Thanks for the links by the way! Though I'm far from understading the whole northern "big picture", but it's necessary to be thorough, isn't it?
Greetings from Hungary!

I do have the photos assembled 12 site photos into a kmz file but now I have a dilema. Due to high photo resolution, the kmz file is about 41 Mb. Is it your experience that this would be prohibitive to up load this onto Google Earth Community or should I go ahead and try? The high resolution shots are great because you can zoom right in to near ground level and see a great deal of detail.

Yes I have done some recreational and commercial diving here in the Yukon. I also have an ROV for underwater camera work - kind of a hobby and part time business. The camera goes into the water more than I do these days. The burbot tunnel burrows are something that, as far as I know, are unique to a few Yukon Lakes. Others have documented the troughs or open slit trench type burrows but I have seen no reports of the large burrows and tunnels I documented in Lake Laberge. Unfortunately Google Earth does not reveal much beyond a few meters of depth so I have not found much in the way of interesting water sites. There are a few wrecks visible from the surface here in the Yukon but they do not fall within the high resolution coverage.

King Point - a favorite place of mine. I spent some time there in 1985/86 doing baseline work on some of the freshwater streams and lakes in the area. Roland Amundsen's winter camp was still visible and we found the grave marker of one of his crew members that died there in 1906 (Gustav Wiik). I think the grave had long since slipped into the ocean (due to permafrost failure) but the sturdy grave marker has been moved back and is probably still there.

Let me know if you think I should upload the file; if not I can look at spiltting it up some. Take care,
Doug

Doug,
I don't think you can upload more than 2 MB with GE to share with everyone. If the -my places- folder gets to big GE's performance becomes erratic and sometimes freezes, always at the wrong moment, and you may loose your work. I would suggest you reduce the files size of each photo to about 100k or even less, make them fit easily on a normal screen.
I would suggest to just resize them, but for the ones where larger detail is useful to understand the permafrost slide or recignize the vegetation you could crop them.

You can create a create a KMZ on your system of 41 MB and send it to interested people by email. I would certainly be interested in seeing the high resolution photos. But we could do that through our emails

Cheers
Jean

I understand what you are saying. I was thinking I may try one image at a time to see if that will work. I am certain you and others would find the high resolution images more revealing than an resized image of 100k. This one will be at about 823k in size. This site is on the Bonnett Plume River not far upstream from the Peel River. I apologise for the low angle of the photo - the horizon is visible in the photo so it does not drape very well over the terrain model. But you should be able to zoom right in on the photo to see much of the detail in this rather large permafrost failure pushing well out into the floodplain. Let me know what you think.

Doug it is a great picture and an impressive slide. The high resolution allows a better identification of the vegetaion types. So give it a try on the moderated forum.

Also this slide started before 1990, although it looks like a rather recent event. I need som time to look at the origin of the slide. When I look at the Google Eart vegetation, it could be an old fire regenation (and fire could be the cause). But the fire would have to have taken place before the 1980's.

Jean