The surge of water flow (SWF) in a river is a dangerous phenomenon that occurs along the water stream. SWF can create an even more dangerous situation called tidal head (TH). High rainfall rates cause river water levels to rise, with high currents leading to TH. Heavy downpour at the upstream creates sudden increase in river water and brings along silts, rocks, branches, and logs, where it rams everything in its path as water travels downstream. In tropical countries, rivers are one of the most popular recreational spots. Tourists engaged in activities such as swimming are unaware of the presence of TH, and they have no time to evacuate. This situation can cause injuries and even fatality. One of the ways to prevent the catastrophic effects of TH is to detect it early. Hence, a TH warning system based on LoRa network technology is developed to prevent accidents or death risks. The system is designed to provide early warning to tourists and the safety personnel monitoring the river and the waterfall. The warning comes in the form of a physical siren and an alert notification via a website accessible through a computer or smartphone. The system prototype consists of LoRa module that remotely transmits warning data with the help of Arduino and water sensors. The prototype is designed to monitor part of the river where the sensors are mounted to the distance where the siren can be heard, and a web application is monitored by the safety personnel or forest wardens to alert the tourists about the occurrence of a TH.