Small Grant for Exploratory Research: Mapping the November 2006 Periglacial Debris Flows on Mount Hood and Mount Rainier

2006年11月的第一个星期，一场由亚热带急流携带的强大风暴在太平洋西北部上空停滞，给该地区带来了创纪录的降雨量。经过六天的强降雨，在俄勒冈州和华盛顿的喀斯喀特山脉的十几个冰川下面引发了主要的泥石流。特别是遭受重创的是山上的冰川排水。胡德山雷尼尔山上胡德，大型泥石流记录在五个主要的排水沟，发生在每一个山坡方面的山。更北的山。在雷尼尔山，泥石流发生在北向冰川下面，如温斯洛普冰川，以前这种泥石流只记录在南，东，西向冰川流域。泥石流的数量和规模及其不寻常的形态分布似乎表明触发机制发生了变化。我们过去关于泥石流触发因素的概念正受到挑战。应对这一挑战的第一步是对这些火山周围的泥石流范围进行全面测绘。正射影像？）在Mt.胡德。目前正在该区域上空获取机载激光雷达数据，以便绘制泥石流的表面高程图。然而，没有计划将可见光/近红外正射图像作为激光雷达采集的一部分。卫星正射图像将提供一种手段，随时显示尚未绘制的2006年11月泥石流的全部范围。光靠激光雷达测高无法区分新旧泥石流，也无法轻易区分原始地带的特征，如裸露的冰川、岩石覆盖的冰川、冰碛和新沉积的物质。可见光/近红外图像需要提供这一重要的背景信息，以正确解释激光雷达测高。目前正在Mt.上空获取LiDAR测高数据和正射纠正航拍照片。这个拟议的项目将利用QuickBird卫星图像（60厘米分辨率）在雷尼尔山上空进行观测，用于与LiDAR数据融合的遮光罩。我们还建议对受影响的排水系统进行初步分析，并与几个泥石流进行一些有限的比较。雷尼尔这是一个紧迫的、对时间敏感的数据问题，因为必须在季节性积雪掩盖该地区和冬季风暴进一步改变泥石流及其起始地点之前获取卫星正射图像。这项工作是一个关键的第一步，制定一个完整的建议，将研究这些冰缘泥石流从地貌学和气候学相结合的角度。更广泛的影响除了地图，表征，并提高对这些卡斯卡迪亚冰缘泥石流的理解，我们将传达我们的研究结果在一个科普期刊文章。我们还将通过网站向有关机构介绍我们的调查结果。Nolin和兰开斯特将部分支持和培训一名研究生，以执行QuickBird和LiDAR数据的正射校正。这项工作与正在拆除土拨鼠大坝的桑迪河流域进行的研究有重要联系。2006年11月的洪水事件大大改变了排水系统的上部，并向下游提供了大量的沉积物。这一纵剖面需要QuickBird图像，以便与2006年11月事件之前获得的以前的航空照片和LiDAR进行比较。

During the first week of November 2006, a powerful storm borne on the subtropical jet stream stalled over the Pacific Northwest inundating the region with record amounts of rainfall. After six days of intense rainfall, major debris flows were triggered below more than a dozen glaciers in the Cascade Range of Oregon and Washington. Especially hard hit were glacier drainages on Mt. Hood and Mt. Rainier. On Mt. Hood, large debris flows were recorded on five major drainages, occurring on every slope aspect of the mountain. Further north on Mt. Rainier, debris flows occurred below north-facing glaciers such as the Winthrop Glacier, where previously such debris flows had only been documented on south, east, and west-facing glacier drainages. The number and size of the debris flows combined with their unusual aspect distribution appear to indicate a change in the triggering mechanisms. Our past conceptions of debris flow triggers are being challenged. The first step in addressing this challenge is a complete mapping of the extent of the debris flows around these volcanoes.This proposal seeks funding to acquire high-resolution orthorectified visible/near-infrared satellite imagery (?orthoimagery?) over Mt. Hood. Airborne LiDAR data are currently being acquired over the region for the purpose of mapping surface elevations of the debris flows. However, visible/near-infrared orthoimagery was not planned as part of that LiDAR acquisition. The satellite orthoimagery will provide the leverage to readily show the full extent of the November 2006 debris flows, which have not yet been mapped. LiDAR altimetry alone is not able to distinguish between old and recent debris flows neither can it easily distinguish between features in the initiation zones such as exposed glacial ice, rock-covered glaciers, moraines and newly deposited material. Visible/near-infrared imagery is needed to provide this important contextual information for correct interpretation of LiDAR altimetry. LiDAR altimetry data and orthorectified aerial photos are currently being acquired over Mt. Rainier to examine the extent of the November 2006 debris flows and floods there.This proposed project will QuickBird satellite imagery (60 cm resolution) over Mt. Hood for fusion with the LiDAR data. We also propose to perform preliminary analyses of affected drainages and perform some limited comparisons with several debris flows on Mt. Rainier. This is an urgent, time-sensitive data issue since the satellite orthoimagery must be acquired before seasonal snowcover masks the area and winter storms further modify the debris flows and their initiation sites. This work is a key first step towards developing a full proposal that will examine these periglacial debris flows from the combined perspectives of geomorphology and climatology.Broader ImpactsIn addition to the maps, characterizations, and improved understanding of these Cascadian periglacial debris flows, we will convey our results in a popular science journal article. We will also present our findings through a website and to concerned agencies. Nolin and Lancaster will partially support and train a graduate student to perform the orthorectification of the QuickBird and LiDAR data. This work has important linkages to ongoing research in the Sandy River watershed where the Marmot Dam is being removed. The November 2006 flood event significantly modified the upper portions of the drainage and provided large amounts of sediment downstream. The QuickBird imagery is needed for this longitudinal section to compare with previous aerial photos and LiDAR that were acquired prior to the November 2006 events.