SGER: Surveying the Southern California Flash Floods of January 2005

2005年1月初，南加州的极端降雨引发了山洪和泥石流，造成了十几人死亡，大规模的基础设施遭到破坏，全国商业中断，数千居民被困。无数的城乡道路、主要高速公路、高速公路、客运和货运铁路被关闭，包括通往洛杉矶和长滩等美国主要港口的货运通道。数千人被迫撤离，数百人失去家园。初步估计损失超过3亿美元。尽管历史上罕见但极端的降雨事件，南加州区域性山洪的产生和发展仍然是一个谜。当风暴从西南方向（而不是更典型的西北方向）逼近时，南加州靠近相对较高、陡峭的海岸地形，这使得南加州特别容易受到山洪暴发的影响。最近的事件为详细研究提供了机会。在大量实物流动证据和临时记录被销毁或无法获得之前，迫切需要开展实地调查和数据收集活动。计划通过雷达、雨量计和我们自己的高分辨率模拟降水和地表径流模型运行，以及灾难性事件的地图，来确定暴洪地区。然后，派出小组调查有关集水区的高水位标志、高海拔地区发生的滑坡或泥流，以及测量其他主要的河床水文特征。各小组还将负责联系各县的水利和防洪控制区，从雨量计、河流流量和其他通常不包括在标准业务预报数据流中的地表数据中收集模拟数据。拟议研究的主要目标是通过及时的实地调查和收集本区域水和洪水控制区的所有现有数据来协助建立一个区域事件数据库，否则这些数据将会丢失。这项工作的最终结果将是建立一个数据库和相关文件，以便对2005年1月南加州的山洪暴发进行区域研究。

0520899GeorgakakosExtreme rainfall in Southern California in early January 2005 led to flash floods andmudslides that caused over a dozen fatalities, and extensive infrastructure damage,interrupted national commerce and stranded thousands of residents. Countless urban and rural roads, major highways, freeways, and passenger and freight railways were shut down, including freight access to major US Ports at Los Angeles and Long Beach. Thousands were forced to evacuate and hundreds lost their homes. Preliminary damage estimates topped $300 million.Regional flash flood production and development in Southern California remains enigmatic despite a history of infrequent but extreme rain events. The proximity of relatively high, steep mountain terrain along the coast makes Southern California uniquely susceptible to flash flooding when storms approach from the southwest (rather than a more typical northwesterly approach). The recent events provide an opportunity for detailed study. A field survey and data collection campaign is urgently needed before a wealth of information in the form of physical flow evidence and temporary records are destroyed or unavailable. It is planned to identify flash flood areas from radar, raingauge and our own nested high resolution simulated precipitation and surface runoff model runs, along with maps of disastrous incidents. Teams will then be deployed to survey catchments of interest targeting high water marks, occurrence of land slides or mudflows in higher elevations, and measurements of other key streambed hydrographic characteristics. Teams will also be charged with contacting Water and Flood Control Districts of various counties to gather analog data from raingauges, streamflow and other surface data not typically included in the standard operational forecast data stream.It is the main objective of the proposed research to assist in the development of a regional event database through timely field surveys and collection of all available data from Water and Flood Control Districts in the region that would otherwise be lost. The final result of the proposed effort will be a database and associated documentation that would allow the regional study of the flash floods of Southern California of January 2005.