{"id":20022794,"date":"2017-08-24T12:30:55","date_gmt":"2017-08-24T07:00:55","guid":{"rendered":"https:\/\/www.thethirdpole.net\/?p=22794"},"modified":"2020-12-21T17:43:46","modified_gmt":"2020-12-21T12:13:46","slug":"what-happens-when-glaciers-and-rivers-collide","status":"publish","type":"post","link":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/","title":{"rendered":"What happens when glaciers and rivers collide?"},"content":{"rendered":"

In most alpine areas, scientists are concerned that\u00a0global warming<\/a>\u00a0and retreating ice will swell glacial lakes and increase the risk of floods downstream. In the Karakoram Mountains of northern Pakistan, the remote Shimshal Valley has the same concerns, but for a somewhat different reason.<\/p>\n

Several of the glaciers that flow into this valley\u00a0surge<\/a>, meaning that they cycle through periods when they flow forward several times faster than usual. \u00a0As the valley is narrow, surging glaciers regularly dam the river that runs through it, creating flood hazards. Floods occur when water pooling up behind the tongue of the advancing glacier suddenly breaks through the natural ice dam and cascades down the gorge.<\/p>\n

Several glaciers flow into the Shimshal Valley perpendicular to the flow of the river, and they have little room to move before they intersect with the water. In recent decades, the four glaciers most prone to blocking the river have been the Khurdopin, Yukshin Gardan, Yazghil and Malungutti.<\/p>\n

\"\"
The\u00a0Operational Land Imager\u00a0(OLI) on\u00a0Landsat 8\u00a0captured this image on May 13 2017.<\/figcaption><\/figure>\n

Of these, Khurdopin has surged most recently. After years of little movement, the glacier began a rapid advance in October 2016, accelerating to a rate of roughly 20 meters (65 feet) per day by the spring of 2017 \u2014 one of the fastest rates observed for a glacier in this region. As ice and sediment pushed into the river, a sizable lake pooled up in March 2017.<\/p>\n

Jakob Steiner<\/a>\u00a0of Utrecht University and the\u00a0Mountain Hydrology Group<\/a>\u00a0has been monitoring the growth of the lake using imagery collected by\u00a0Landsat 8<\/a>\u00a0and Planet Labs, a commercial satellite company. By July 2017, the river had carved an outlet through the glacial debris before the lake could grow extremely large, but Steiner\u2019s group continued to keep a watchful eye because of how much debris the glacier pushed into the river. The surge increased the thickness of the end of the glacier by as much as 80 meters (260 feet), according to Steiner. The photograph above, taken by Waheed Anwar of\u00a0Focus Pakistan<\/a>, shows the tip of the sediment-coated glacier pushing into the river on May 15 2017. The camera is pointed upstream toward Khurdopin glacier.<\/p>\n

Read more:\u00a0Experts explore reasons for glacier collapses in Tibet<\/a><\/strong><\/p>\n

The rapid draining of even a relatively small lake can have dramatic consequences downstream. In late July 2017, the size of the lake dropped from 100,000 square meters to about 40,000 square meters in a few days \u2014 a rapid enough change to produce a flood downstream that\u00a0damaged bridges, farmland, and a key road<\/a>. By August 3 2017, the lake had completely drained. The flooding and road damage left hundreds of people stranded<\/a> in the Shimshal Valley awaiting evacuation by helicopter.<\/p>\n

Historical records show that surging glaciers have triggered at least 20 of these\u00a0glacial lake outburst floods<\/a>\u00a0over the past century, making the valley one of the most vulnerable in the Karakoram Mountains. Past floods have caused damage with such frequency that villagers in the river towns of Pasu and Shimshal established a beacon warning system. In the spring, more than 30 outposts were set up on visible hillsides along a 90-kilometre span of the gorge. When a flood occurred during the night, the outposts lit a series of bonfires to warn people downstream. During the day, they used the sound of gunfire to pass the message. The system has been replaced with cell phones, but the service is spotty enough in this valley that floods still sometimes take people by surprise.<\/p>\n

Surging glaciers are not the only cause of flood hazards in this area. In the nearby Hunza River Valley in 2010, a massive landslide blocked the river and\u00a0created a large lake<\/a>. Though the lake now flows over the dam, the possibility that this natural dam could eventually breach elevates flood risks for towns and villages downstream.<\/p>\n

This blog first appeared on<\/em>\u00a0NASA Earth Observatory<\/a>.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Scientists worry that global warming and retreating ice will swell glacial lakes and increase flood risks. The same concerns are echoed in Pakistan’s Shimshal Valley, but for a different reason<\/p>\n","protected":false},"author":2911,"featured_media":20022820,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[761],"tags":[519,20000192],"hashtags":[],"country":[20000112],"class_list":["post-20022794","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-climate","tag-climate-impacts","tag-disasters","country-pakistan"],"acf":[],"yoast_head":"\nWhat happens when glaciers and rivers collide? | Dialogue Earth<\/title>\n<meta name=\"description\" content=\"Scientists worry that global warming and retreating ice will swell glacial lakes and increase flood risks. The same concerns are echoed in Pakistan's Shimshal Valley, but for a different reason\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"What happens when glaciers and rivers collide?\" \/>\n<meta property=\"og:description\" content=\"Scientists worry that global warming and retreating ice will swell glacial lakes and increase flood risks. The same concerns are echoed in Pakistan's Shimshal Valley, but for a different reason\" \/>\n<meta property=\"og:url\" content=\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/\" \/>\n<meta property=\"og:site_name\" content=\"Dialogue Earth\" \/>\n<meta property=\"article:published_time\" content=\"2017-08-24T07:00:55+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2020-12-21T12:13:46+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/dialogue.earth\/content\/uploads\/2017\/08\/9776750541_3979baa359_o-e1503499385709.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"1020\" \/>\n\t<meta property=\"og:image:height\" content=\"673\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"Katherine Purvis\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/\"},\"author\":{\"name\":\"Katherine Purvis\",\"@id\":\"https:\/\/dialogue.earth\/en\/#\/schema\/person\/7d4ebac737538a8cf234276e3c9c1eef\"},\"headline\":\"What happens when glaciers and rivers collide?\",\"datePublished\":\"2017-08-24T07:00:55+00:00\",\"dateModified\":\"2020-12-21T12:13:46+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/\"},\"wordCount\":649,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\/\/dialogue.earth\/en\/#organization\"},\"image\":{\"@id\":\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/dialogue.earth\/content\/uploads\/2017\/08\/9776750541_3979baa359_o-e1503499385709.jpg\",\"keywords\":[\"Climate impacts\",\"Disasters\"],\"articleSection\":[\"Climate\"],\"inLanguage\":\"en\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/\",\"url\":\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/\",\"name\":\"What happens when glaciers and rivers collide? | Dialogue Earth\",\"isPartOf\":{\"@id\":\"https:\/\/dialogue.earth\/en\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/dialogue.earth\/content\/uploads\/2017\/08\/9776750541_3979baa359_o-e1503499385709.jpg\",\"datePublished\":\"2017-08-24T07:00:55+00:00\",\"dateModified\":\"2020-12-21T12:13:46+00:00\",\"description\":\"Scientists worry that global warming and retreating ice will swell glacial lakes and increase flood risks. The same concerns are echoed in Pakistan's Shimshal Valley, but for a different reason\",\"breadcrumb\":{\"@id\":\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#breadcrumb\"},\"inLanguage\":\"en\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en\",\"@id\":\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#primaryimage\",\"url\":\"https:\/\/dialogue.earth\/content\/uploads\/2017\/08\/9776750541_3979baa359_o-e1503499385709.jpg\",\"contentUrl\":\"https:\/\/dialogue.earth\/content\/uploads\/2017\/08\/9776750541_3979baa359_o-e1503499385709.jpg\",\"width\":1020,\"height\":673,\"caption\":\"An aeriel view over glaciers in the Karakoram Mountain range [Credit: NASA Johnson]\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/dialogue.earth\/en\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"What happens when glaciers and rivers collide?\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/dialogue.earth\/en\/#website\",\"url\":\"https:\/\/dialogue.earth\/en\/\",\"name\":\"Dialogue Earth\",\"description\":\"Global climate and environment news\",\"publisher\":{\"@id\":\"https:\/\/dialogue.earth\/en\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/dialogue.earth\/en\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/dialogue.earth\/en\/#organization\",\"name\":\"\u5bf9\u8bdd\u5730\u7403\",\"url\":\"https:\/\/dialogue.earth\/en\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en\",\"@id\":\"https:\/\/dialogue.earth\/en\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/dialogue.earth\/content\/uploads\/2024\/04\/Dialogue-Earth-Symbol-Logo_Black-Text.png\",\"contentUrl\":\"https:\/\/dialogue.earth\/content\/uploads\/2024\/04\/Dialogue-Earth-Symbol-Logo_Black-Text.png\",\"width\":256,\"height\":256,\"caption\":\"\u5bf9\u8bdd\u5730\u7403\"},\"image\":{\"@id\":\"https:\/\/dialogue.earth\/en\/#\/schema\/logo\/image\/\"},\"sameAs\":[\"https:\/\/twitter.com\/DialogueEarth_\",\"\",\"https:\/\/www.facebook.com\/DialogueEarth.English\",\"https:\/\/www.instagram.com\/dialogue.earth\/\",\"https:\/\/www.linkedin.com\/company\/dialogueearth\/\"],\"publishingPrinciples\":\"https:\/\/dialogue.earth\/en\/about\/\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/dialogue.earth\/en\/#\/schema\/person\/7d4ebac737538a8cf234276e3c9c1eef\",\"name\":\"Katherine Purvis\",\"description\":\"Katherine Purvis is the assistant editor for The Third Pole.\",\"url\":\"https:\/\/dialogue.earth\/en\/author\/katherinepurvis\/\",\"sameAs\":[\"https:\/\/dialogue.earth\/en\/author\/adam-voiland\/\"]}]}<\/script>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"What happens when glaciers and rivers collide? | Dialogue Earth","description":"Scientists worry that global warming and retreating ice will swell glacial lakes and increase flood risks. The same concerns are echoed in Pakistan's Shimshal Valley, but for a different reason","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/","og_locale":"en_US","og_type":"article","og_title":"What happens when glaciers and rivers collide?","og_description":"Scientists worry that global warming and retreating ice will swell glacial lakes and increase flood risks. The same concerns are echoed in Pakistan's Shimshal Valley, but for a different reason","og_url":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/","og_site_name":"Dialogue Earth","article_published_time":"2017-08-24T07:00:55+00:00","article_modified_time":"2020-12-21T12:13:46+00:00","og_image":[{"width":1020,"height":673,"url":"https:\/\/dialogue.earth\/content\/uploads\/2017\/08\/9776750541_3979baa359_o-e1503499385709.jpg","type":"image\/jpeg"}],"author":"Katherine Purvis","twitter_card":"summary_large_image","schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#article","isPartOf":{"@id":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/"},"author":{"name":"Katherine Purvis","@id":"https:\/\/dialogue.earth\/en\/#\/schema\/person\/7d4ebac737538a8cf234276e3c9c1eef"},"headline":"What happens when glaciers and rivers collide?","datePublished":"2017-08-24T07:00:55+00:00","dateModified":"2020-12-21T12:13:46+00:00","mainEntityOfPage":{"@id":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/"},"wordCount":649,"commentCount":0,"publisher":{"@id":"https:\/\/dialogue.earth\/en\/#organization"},"image":{"@id":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#primaryimage"},"thumbnailUrl":"https:\/\/dialogue.earth\/content\/uploads\/2017\/08\/9776750541_3979baa359_o-e1503499385709.jpg","keywords":["Climate impacts","Disasters"],"articleSection":["Climate"],"inLanguage":"en","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/","url":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/","name":"What happens when glaciers and rivers collide? | Dialogue Earth","isPartOf":{"@id":"https:\/\/dialogue.earth\/en\/#website"},"primaryImageOfPage":{"@id":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#primaryimage"},"image":{"@id":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#primaryimage"},"thumbnailUrl":"https:\/\/dialogue.earth\/content\/uploads\/2017\/08\/9776750541_3979baa359_o-e1503499385709.jpg","datePublished":"2017-08-24T07:00:55+00:00","dateModified":"2020-12-21T12:13:46+00:00","description":"Scientists worry that global warming and retreating ice will swell glacial lakes and increase flood risks. The same concerns are echoed in Pakistan's Shimshal Valley, but for a different reason","breadcrumb":{"@id":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#breadcrumb"},"inLanguage":"en","potentialAction":[{"@type":"ReadAction","target":["https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/"]}]},{"@type":"ImageObject","inLanguage":"en","@id":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#primaryimage","url":"https:\/\/dialogue.earth\/content\/uploads\/2017\/08\/9776750541_3979baa359_o-e1503499385709.jpg","contentUrl":"https:\/\/dialogue.earth\/content\/uploads\/2017\/08\/9776750541_3979baa359_o-e1503499385709.jpg","width":1020,"height":673,"caption":"An aeriel view over glaciers in the Karakoram Mountain range [Credit: NASA Johnson]"},{"@type":"BreadcrumbList","@id":"https:\/\/dialogue.earth\/en\/climate\/what-happens-when-glaciers-and-rivers-collide\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/dialogue.earth\/en\/"},{"@type":"ListItem","position":2,"name":"What happens when glaciers and rivers collide?"}]},{"@type":"WebSite","@id":"https:\/\/dialogue.earth\/en\/#website","url":"https:\/\/dialogue.earth\/en\/","name":"Dialogue Earth","description":"Global climate and environment news","publisher":{"@id":"https:\/\/dialogue.earth\/en\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/dialogue.earth\/en\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en"},{"@type":"Organization","@id":"https:\/\/dialogue.earth\/en\/#organization","name":"\u5bf9\u8bdd\u5730\u7403","url":"https:\/\/dialogue.earth\/en\/","logo":{"@type":"ImageObject","inLanguage":"en","@id":"https:\/\/dialogue.earth\/en\/#\/schema\/logo\/image\/","url":"https:\/\/dialogue.earth\/content\/uploads\/2024\/04\/Dialogue-Earth-Symbol-Logo_Black-Text.png","contentUrl":"https:\/\/dialogue.earth\/content\/uploads\/2024\/04\/Dialogue-Earth-Symbol-Logo_Black-Text.png","width":256,"height":256,"caption":"\u5bf9\u8bdd\u5730\u7403"},"image":{"@id":"https:\/\/dialogue.earth\/en\/#\/schema\/logo\/image\/"},"sameAs":["https:\/\/twitter.com\/DialogueEarth_","","https:\/\/www.facebook.com\/DialogueEarth.English","https:\/\/www.instagram.com\/dialogue.earth\/","https:\/\/www.linkedin.com\/company\/dialogueearth\/"],"publishingPrinciples":"https:\/\/dialogue.earth\/en\/about\/"},{"@type":"Person","@id":"https:\/\/dialogue.earth\/en\/#\/schema\/person\/7d4ebac737538a8cf234276e3c9c1eef","name":"Katherine Purvis","description":"Katherine Purvis is the assistant editor for The Third Pole.","url":"https:\/\/dialogue.earth\/en\/author\/katherinepurvis\/","sameAs":["https:\/\/dialogue.earth\/en\/author\/adam-voiland\/"]}]}},"_links":{"self":[{"href":"https:\/\/dialogue.earth\/en\/wp-json\/wp\/v2\/posts\/20022794","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dialogue.earth\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dialogue.earth\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dialogue.earth\/en\/wp-json\/wp\/v2\/users\/2911"}],"replies":[{"embeddable":true,"href":"https:\/\/dialogue.earth\/en\/wp-json\/wp\/v2\/comments?post=20022794"}],"version-history":[{"count":0,"href":"https:\/\/dialogue.earth\/en\/wp-json\/wp\/v2\/posts\/20022794\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/dialogue.earth\/en\/wp-json\/wp\/v2\/media\/20022820"}],"wp:attachment":[{"href":"https:\/\/dialogue.earth\/en\/wp-json\/wp\/v2\/media?parent=20022794"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dialogue.earth\/en\/wp-json\/wp\/v2\/categories?post=20022794"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dialogue.earth\/en\/wp-json\/wp\/v2\/tags?post=20022794"},{"taxonomy":"hashtags","embeddable":true,"href":"https:\/\/dialogue.earth\/en\/wp-json\/wp\/v2\/hashtags?post=20022794"},{"taxonomy":"country","embeddable":true,"href":"https:\/\/dialogue.earth\/en\/wp-json\/wp\/v2\/country?post=20022794"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}