当短时强降水发生时，雨水来不及充分渗入深层土壤，大部分会在地表形成快速流动的水流。这些水流 冲刷地表的松散土石并将其裹挟，易形成泥石流。同时，表层土壤在短时间内因雨水饱和，就像被泡软 的蛋糕一样失去原有的稳定性，容易发生浅层滑坡。 而在持续性降水的作用下，雨水会慢慢渗入土壤深层，就像给山体"喝水"。水分顺着岩土体中的孔隙或 裂隙不断渗透，导致岩土体自重增加并发生泥化、软化现象，坡体强度和稳定性降低。当深层土壤和岩 层之间的摩擦力被水分削弱到一定程度时，就可能发生深度较大的滑坡，土石量大、破坏性强。 即使已经雨过天晴，也不意味着风险解除。雨水渗到土壤中是一个持续的过程。雨停后水分仍在向土壤 深层渗透，可能数天后山体内部的土壤才达到饱和状态，从而诱发滑坡。此外，雨后阳光照射使表层土 石中的水分大量蒸发，岩土体中收缩裂缝易导致土石层松动，在重力作用下也易发生滑坡。 气象专家提醒，正值暑期旅游旺季，建议景区加强防范措施，游客要根据天气预报合理安排行程。此 外，长江流域中小河流密布，需要注意防范可能发生的中小河流洪水。 近几天，一条沿着长江走向的雨带让川渝至苏皖一带降雨频繁。降水分布不均匀、单点强度大，是这条 雨带的突 ...

山洪来临前有什么征兆？ 山洪的发生往往不是因为你所在的地方下雨，而是上游甚至上上游正在下暴雨。当你突然听到类似火车轰鸣的沉闷的轰隆声，别以为是雷声，那很可能是上 游的洪水撞击石头的声响。要是清澈的水流突然变得浑浊，洪水恐怕已经近在咫尺了。 遇到山洪该怎么办？ 山洪来临前有哪些特征？ 山体滑坡有哪些特征？ 据水利部和中国气象局7月2日18时联合发布红色山洪灾害气象预警： 预计，7月2日20时至3日20时，四川中部和北部、甘肃南部等地部分地区发生山洪灾害可能性大（橙色预警），其中，四川北部、甘肃南部局地发生山洪灾 害可能性很大（红色预警）。其他地区也可能因局地短历时强降水引发山洪灾害。 近期我国多地持续出现强降雨天气，极易引发山洪、山体滑坡等自然灾害，威胁大家的生命财产安全！掌握科学的避险知识，在关键时刻能帮我们化险为 夷。 什么是山洪？ 山洪是指山区溪沟中发生的暴涨洪水。常发生在山沟附近、溪河两边位置较低处、双河口交叉处、河道拐弯凸岸等地。山洪具有突发性，水量集中、流速 大、冲刷破坏力强等特点。 2.被洪水包围：尽快联系消防、公安等救援部门，报告准确方位和险情，同时通过火光、浓烟、旗语或呼喊等方式主动求救； 3 ...

Summary of Key Points Core Viewpoint - The province is expected to experience intermittent rainfall from July 2 to July 8, with significant rainfall and potential severe weather events such as thunderstorms, strong winds, and hail due to the influence of subtropical high pressure and upper-level troughs [1][2]. Group 1: Weather Impact - The rainfall in northern Shaanxi is expected to be prolonged, while western and northwestern Guanzhong will experience intense rainfall, leading to high cumulative precipitation and short-duration heavy rain [1]. - There is a high risk of secondary disasters such as mountain floods, geological hazards, and urban flooding due to the heavy rainfall, particularly in northern Shaanxi where some small and medium rivers are nearing warning levels [1]. - High temperatures in eastern Guanzhong and eastern Ankang may trigger localized severe convective weather, including thunderstorms and hail [1]. Group 2: Agricultural Recommendations - Agricultural experts recommend timely irrigation in areas like southern Xianyang, northern Xi'an, and Weinan, where soil moisture is lacking, and to implement measures such as spraying and shading in kiwi and grape planting areas to prevent sunburn from high temperatures [1]. - Farmers in northern Shaanxi and western Guanzhong should clear drainage ditches in advance to mitigate the adverse effects of water accumulation on crops and enhance pest monitoring and control [1]. - In apple and kiwi production areas in northern Shaanxi and western Guanzhong, precautions should be taken against wind and hail damage to branches and fruits [1]. Group 3: Transportation and Tourism - The rainfall is causing slippery conditions on roads and railways in northern Shaanxi, western and northwestern Guanzhong, with specific highways and rail lines experiencing significant rainfall and high risks of secondary disasters affecting transportation safety [2]. - With the increase in tourists during the summer, local tourism departments are advised to monitor weather forecasts and warnings to mitigate the adverse impacts of severe weather on tourist attractions and outdoor facilities [2].