Dear Spring, I would agree, the less shadowing the better, but that is obviously a function of timing, the angle from which the image is captured, and then steepness of the relief...
Based on the information I've examined before, there isn't much we can do, as we are at the mercy of the available data...I've not had a chance to check anything out specifically yet, so can't comment on the issues we may have in the Nepal dataset...however, anything is better than nothing... As soon as possible, we do need to try and get scouts reporting on the integrities of the dams, and (at best) surveying with drones and the like. However, I'm sure priorities are elsewhere and this will be slow to occur. Thanks, Sam Inglis MSc <http://hk.linkedin.com/in/saminglis/> <https://www.facebook.com/sam.inglis.92> <https://twitter.com/the_ice_man_24>[image: +852 6036 8750] <(+852)+6036+8750>[image: sam_urai_24] <sam_urai_24> On 14 May 2015 at 01:46, Springfield Harrison <stellar...@gmail.com> wrote: > Further to my previous . . . > > Due to the high relief in the risk area, high off-nadir angle imagery may > be less useful. There may be too much distortation or obscured areas. > > On the other hand, are there other choices? > > Cheers . . . . . Spring > Samsung Tab 4 > On May 13, 2015 9:49 AM, "Sam Inglis" <sam.ing...@gmail.com> wrote: > >> Dear Steve, >> >> I worked for Professor John Reynolds, the man who led the research which >> revealed the instability of the dam at Tsho Rolpa. I have read about the >> site extensively in his company archives, which was conducting research >> there from at least 1998, to present I believe. >> >> He is convinced that Tsho Rolpa is the far more dangerous of the two >> majorly dangerous glacial lakes in Nepal, the other being Imja. I would >> certainly encourage a very close examination of the region - in particular >> there is an ice-core, which has been melting for some time, in the terminal >> entraining moraine dam - if I remember correctly, it is at the southern end >> (the terminus), under the northwestern section of the dam. If there is any >> sign of water seeping from the dam itself, or any slumping in that >> section...I would recommend some very drastic and rapid movements to get >> people moving from downstream. >> >> Any destabilisation of surrounding slopes, or cracking of the glacier >> snout are other things to look out for. >> >> I have loaded one of his many papers on the region, "*Glacial hazard >> assessment at Tsho Rolpa, Rolwaling, Central Nepa*l", into my Google >> Drive folder for your reference ( >> https://drive.google.com/folderview?id=0B3qRfjnIhqMhfm44dlZnM2x3Um1ia09mV2FwNHhLQmR2TDZKNVBaNFlyNENERkNZTkNmOU0&usp=sharing >> ). >> >> There are a large number of papers assessing the potential, identifying >> what to look for, etc. >> >> If you have specific questions, I'm always happy to help and, as >> suggested before, would consider throwing together a quick handbook to help >> with identification of the key risks. >> >> Thanks, >> >> >> Sam Inglis MSc >> >> <http://hk.linkedin.com/in/saminglis/> >> <https://www.facebook.com/sam.inglis.92> >> <https://twitter.com/the_ice_man_24>[image: +852 6036 8750] >> <(+852)+6036+8750>[image: sam_urai_24] <sam_urai_24> >> >> On 14 May 2015 at 00:25, Steve Bower <sbo...@gmavt.net> wrote: >> >>> Tsho Rolpa, northern Dolakha district, is another glacial lake renowned >>> for having an unstable natural dam, putting thousands at risk downstream. >>> >>> http://www.bigmaybe.com/learn?s=Tsho_Rolpa >>> >>> Perhaps there is an existing assessment of natural dams at risk of >>> failing. >>> >>> Steve >>> >>> On Wed, May 13, 2015 at 10:59 AM, Sam Inglis <sam.ing...@gmail.com> >>> wrote: >>> >>>> Dear All, >>>> >>>> I agree totally, the hydropower issues are enormous - a very important >>>> case study of the 1985 Dig Tsho glacial lake disaster, studied by Vuichard >>>> & Zimmerman in 1987, revealed the destructive potential of Glacial Lake >>>> Outburst Floods (GLOFs) and LLOFs. >>>> >>>> Please see via: >>>> https://drive.google.com/open?id=0B3qRfjnIhqMhfm44dlZnM2x3Um1ia09mV2FwNHhLQmR2TDZKNVBaNFlyNENERkNZTkNmOU0&authuser=0 >>>> >>>> I would be happy to scan the satellite imagery for viable sites, but >>>> the main issue is LLOFs (Landslide-dammed Lake Outburst Floods) in the >>>> immediate future. In order to identify these, the HOT team needs to make >>>> current satellite imagery available (my apologies if this has already been >>>> done). >>>> >>>> I am also quite busy at the moment, and very sadly (selfishly) cannot >>>> commit to mapping the situation in the next day or so. However, the key >>>> things to be looking out for are* landslide-dammed lakes*. They are >>>> highly destructive, enormously unstable, filled by glacial melt waters, >>>> debris, rainwater, and anything else entrained by the waters, and very >>>> deadly. >>>> >>>> These features form very rapidly - a 6km lake formed and burst within a >>>> couple of days along the Sutlej River, due to a combination of internal >>>> pressure (the river has a naturally high discharge rate), compounded by a >>>> cloudburst. >>>> >>>> Also keep an eye out for shifting glaciers, as their migrations will >>>> release sub- or englacial (internal) meltwater - the slipping of glaciers >>>> down valley may have blocked sections of rivers, and would create very >>>> dangerous situations. >>>> >>>> I could try and come up with a brief handbook on what to look out for, >>>> so that the features can be identified, in the next 4 days? If this >>>> agreeable, someone should just give me an idea of what the team needs, and >>>> I'll work to spec! >>>> >>>> Thanks, >>>> >>>> Sam Inglis MSc >>>> >>>> <http://hk.linkedin.com/in/saminglis/> >>>> <https://www.facebook.com/sam.inglis.92> >>>> <https://twitter.com/the_ice_man_24>[image: +852 6036 8750] >>>> <(+852)+6036+8750>[image: sam_urai_24] <sam_urai_24> >>>> >>>> On 13 May 2015 at 14:36, amrit karmacharya <amrit...@gmail.com> wrote: >>>> >>>>> hi sam >>>>> >>>>> all of the hydropower plants in nepal are dependent on glacial rivers. >>>>> is it possible to identify lake formation and bursting in the areas >>>>> upstream of these powerplants? losing power source would be terrible. >>>>> On 13 May 2015 04:44, "Robert Banick" <rban...@gmail.com> wrote: >>>>> >>>>>> Hi Sam, >>>>>> >>>>>> I think honestly you’re better placed to tell us how you can help >>>>>> than the other way around. Most of us aren’t glacial lake experts :-) >>>>>> >>>>>> My first thought is that you can trace lakes in the affected areas >>>>>> into OSM. The second would be to help us understand what, if any, risks >>>>>> can >>>>>> result from lakes being dammed by landslides. Are there risks associated >>>>>> with eventual bursts? Do we need to create data in OSM and then try to >>>>>> model these risks in GIS software packages? >>>>>> >>>>>> You tell us! >>>>>> >>>>>> Cheers, >>>>>> Robert >>>>>> >>>>>> — >>>>>> Sent from Mailbox <https://www.dropbox.com/mailbox> >>>>>> >>>>>> >>>>>> On Tue, May 12, 2015 at 2:10 AM, Sam Inglis <sam.ing...@gmail.com> >>>>>> wrote: >>>>>> >>>>>>> Dear HOT Team, >>>>>>> >>>>>>> My name is Sam Inglis, and my background is in glacial lake >>>>>>> detection, identification and mapping, and was the first person to >>>>>>> identify >>>>>>> all glacial lakes in the North Patagonian Icefield, Chile. I am familiar >>>>>>> with Himalayan mountain ranges, and studied large swathes of the >>>>>>> Indo-Tibetan catchment of the Sutlej River, which runs from near Mt >>>>>>> Kailash, transects Himachal Pradesh, and terminates in Pakistani >>>>>>> territory. >>>>>>> >>>>>>> I have previously not engaged much in communal, open-source, >>>>>>> reactive disaster mapping, but have been adding to the OSM database in >>>>>>> Nepal sporadically over the past two weeks, when time has permitted. >>>>>>> >>>>>>> Yesterday, I saw that NASA had posted an article >>>>>>> <http://was%20the%20first%20person%20to%20identify%20all%20glacial%20lakes%20in%20the%20North%20Patagonian%20Icefield,%20Chile,> >>>>>>> on the formation of landslide-dammed lakes along Nepal's rivers, near >>>>>>> Gorkha, and was wondering how I can best contribute to enhancing the >>>>>>> understanding of the features? How can I help with such hazard >>>>>>> detection & >>>>>>> analysis? >>>>>>> >>>>>>> Thanks, and I look forward to hearing back from you and the team! >>>>>>> >>>>>>> Keep up the great work! >>>>>>> >>>>>>> Sam Inglis MSc >>>>>>> >>>>>>> <http://hk.linkedin.com/in/saminglis/> >>>>>>> <https://www.facebook.com/sam.inglis.92> >>>>>>> <https://twitter.com/the_ice_man_24>[image: +852 6036 8750] >>>>>>> <(+852)+6036+8750>[image: sam_urai_24] <sam_urai_24> >>>>>>> >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> HOT mailing list >>>>>> HOT@openstreetmap.org >>>>>> https://lists.openstreetmap.org/listinfo/hot >>>>>> >>>>>> >>>> >>>> _______________________________________________ >>>> HOT mailing list >>>> HOT@openstreetmap.org >>>> https://lists.openstreetmap.org/listinfo/hot >>>> >>>> >>> >> >> _______________________________________________ >> HOT mailing list >> HOT@openstreetmap.org >> https://lists.openstreetmap.org/listinfo/hot >> >>
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