{"id":29387,"date":"2018-12-05T02:28:55","date_gmt":"2018-12-05T02:28:55","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=29387"},"modified":"2018-12-05T03:35:25","modified_gmt":"2018-12-05T03:35:25","slug":"malibu-mudflows-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2018\/12\/05\/malibu-mudflows-1\/","title":{"rendered":"Malibu: Planet Labs images of the first round of mudflows"},"content":{"rendered":"<h4>Malibu: Planet Labs images of the first round of mudflows<\/h4>\n<p>One of the <a href=\"https:\/\/www.google.com\/url?sa=t&amp;rct=j&amp;q=&amp;esrc=s&amp;source=newssearch&amp;cd=15&amp;cad=rja&amp;uact=8&amp;ved=0ahUKEwjZ4ajW0IffAhXPQd4KHcIdDrsQqQIIVygAMA4&amp;url=http%3A%2F%2Fthesource.com%2F2018%2F11%2F21%2Fcalifornia-mudslides%2F&amp;usg=AOvVaw3iqDXSZI8W5MaJRA8DadFK\">potentially disastrous impacts of the recent wildfires in California<\/a> is the <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2014\/02\/21\/wildfire-debris-flow-potential\/\">vulnerability of the now bare soil to highly destructive mudflows<\/a>.\u00a0 Similar processes have been seen <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2018\/01\/16\/montecito-debris-flows-1\/\">elsewhere in California,<\/a> and <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2009\/02\/09\/australian-wildfires-and-risks-of-increased-erosion-rates\/\">indeed worldwide<\/a>.\u00a0 The fires have occurred at the start of the period in which extremely heavy rainfall, associated with <a href=\"https:\/\/www.sacbee.com\/news\/weather\/article206022434.html\">atmospheric river events<\/a>, can occur.\u00a0 The potential impacts are serious.<\/p>\n<p><a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a> have captured a high resolution SkySat image of a part of Malibu following the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Woolsey_Fire\">Woolsey fire<\/a> and then <a href=\"https:\/\/ktla.com\/2018\/11\/29\/rain-triggers-mudslide-in-malibu-residents-told-to-evacuate-immediately\/\">the heavy rainfall last week<\/a>.\u00a0 They have kindly provided three images of the area.\u00a0 The first image, collected on 31st August 2017, predates the fire:-<\/p>\n<div id=\"attachment_29388\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-29388\" class=\"size-full wp-image-29388\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2018\/12\/malibu_20170831_ssc2-e1543975241734.jpg\" alt=\"Malibu\" width=\"640\" height=\"360\" \/><p id=\"caption-attachment-29388\" class=\"wp-caption-text\"><a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a> SkySat image of a part of Malibu prior to the fire on 31st August 2017. Image copyright of <a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a> 2018, used with permission.<\/p><\/div>\n<p>.<\/p>\n<p>The second image was collected on 28th November 2018, after the fire:-<\/p>\n<div id=\"attachment_29391\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-29391\" class=\"size-full wp-image-29391\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2018\/12\/malibu_20181128_ssc3-e1543975389882.jpg\" alt=\"Malibu\" width=\"640\" height=\"360\" \/><p id=\"caption-attachment-29391\" class=\"wp-caption-text\"><a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a> SkySat image of a part of Malibu after the fire on 28th November 2018. Image copyright of <a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a> 2018, used with permission.<\/p><\/div>\n<p>.<\/p>\n<p>The extensive fire damage to the vegetation in the hilly area is very clearly seen.\u00a0 This is this damage that has made the area vulnerable to heavy rainfall.\u00a0 Finally, this image shows the same area after the first round of heavy rainfall:-<\/p>\n<div id=\"attachment_29392\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-29392\" class=\"size-full wp-image-29392\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2018\/12\/malibu_20181201_ssc9-e1543975548433.jpg\" alt=\"Malibu\" width=\"640\" height=\"360\" \/><p id=\"caption-attachment-29392\" class=\"wp-caption-text\"><a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a> SkySat image of a part of Malibu after the first round of heavy rainfall, collected on 1st December 2018. Image copyright of <a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a> 2018, used with permission.<\/p><\/div>\n<p>.<\/p>\n<p>The image shows extensive stripping of top soil by the heavy rainfall, and the formation of gullies, especially on the right side of the image.\u00a0 This is a more detailed image of this area:-<\/p>\n<div id=\"attachment_29395\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-29395\" class=\"size-full wp-image-29395\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2018\/12\/18_12-Malibu-1-e1543975834867.jpg\" alt=\"Malibu\" width=\"640\" height=\"325\" \/><p id=\"caption-attachment-29395\" class=\"wp-caption-text\">Detail of a <a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a> SkySat image of a part of Malibu after the first round of heavy rainfall, collected on 1st December 2018. Image copyright of <a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a> 2018, used with permission.<\/p><\/div>\n<p>.<\/p>\n<p>This is a remarkable image, showing extensive shallow stripping and gullying, with the gullies providing direct connection to the river channels.\u00a0 The ways in which huge numbers of small flow structures all connect to the same channel provides the potential for the massive downslope impacts.<\/p>\n<p>The climate emergency (sometimes less well described as climate change) is very much in the news, and the landslide community is worrying about he impacts on mass movements.\u00a0 This example is a beautiful, tragic illustration of the problem &#8211; increased drought is increasing the risk of forest fires; increased rainfall intensities then allow more dynamic mobilisation of the debris to form mudflows.<\/p>\n<h4>Reference<\/h4>\n<p><a href=\"https:\/\/www.planet.com\/\">Planet Team (2018)<\/a>. Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. <a href=\"https:\/\/www.planet.com\/\">https:\/\/www.planet.com\/<\/a>.\u00a0 Especially thanks to Robert Simmon for his work on the images,<\/p>\n<!-- AddThis Advanced Settings generic via filter on the_content --><!-- AddThis Share Buttons generic via filter on the_content -->","protected":false},"excerpt":{"rendered":"<p>Malibu &#8211; Planet Labs have captured remarkable before and after SkySat images of the first round of mudflows following the recent wildfires<!-- AddThis Advanced Settings generic via filter on wp_trim_excerpt --><!-- AddThis Share Buttons generic via filter on wp_trim_excerpt --><\/p>\n","protected":false},"author":22,"featured_media":29395,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7203],"tags":[137,469,641,1205,48,170],"class_list":["post-29387","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-planet-labs","tag-california","tag-featured","tag-mudflow","tag-planet-labs","tag-usa","tag-wildfire"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/29387","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/users\/22"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/comments?post=29387"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/29387\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/29395"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=29387"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=29387"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=29387"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}