## 1 Introduction  
Coastal areas, characterized by their dynamic interplay between land and sea, are important ecosystems that host varied biodiversity, support economies through fisheries and tourism, and serve as critical buffers against natural hazards [1, 2, 3, 4]. Numerous studies substantiate the dynamic nature of global coasts. For instance, about 24% of the world's sandy beaches were continuously losing ground at a rate of more than 0.5 m per year from 1984 to 2016 [5], which is attributed to exposure to various environmental factors such as hydrodynamics (e.g., tides, waves, and alongshore currents), extreme events (e.g., tropical cyclones, floods, and drought), and the rising sea levels associated with climate change [6, 7]. A tidal flat (also known as the intertidal zone) is a coastal landscape with expanses of flat, muddy, or sandy areas exposed during low tide and submerged during high tide, observable along the coastlines with strong tidal dynamics [8]. It is characterized by the rise and fall of tides, creating a dynamic environment and continuous transformations influenced mainly by tidal processes [9]. Typically, the regional low-lying topography within the tidal flat is referred to as a tidal Creek or tidal channel [10, 11]. Should the tide elevate swiftly, leading to a considerable depth in the tidal Creek, this poses a potential risk to individuals [12]. In this context, the tidal flat formed swiftly and changing rapidly in the southeast corner of Shanghai stands as a testament to the complexity of coastal topography, particularly marked by the characteristics of complex spatial features and frequent temporal evolution that are not yet comprehensively understood. The variations in the tidal flat area with time and the relationship between the tidal level and the tidal flat area revealed that the tidal flat was in a rapid accretion phase before 2018, which then changed to erosion [13]. While this tidal flat attracts numerous individuals during low tidal levels for recreational pursuits, there exists a significant gap in recognizing and comprehending the associated risks when seawater levels rise. The actual situation is that individuals who visit the lower tidal flat during the low-tide period often instinctively return to the land when seawater approaches their position. However, owing to the non-linear changes in topography, the seawater might rise from the onshore direction (see Figure 1). This risk may not be readily apparent, particularly to individuals who are not familiar with the local natural conditions or possess limited oceanic knowledge. Figure 1: (**A**) Aerial photograph captured during the rising tidal level, with the black solid line indicating the section position and the blue arrows illustrating seawater submerging the tidal channel initially and subsequently surrounding the lower tidal flat; (**B**) the scenario where individuals recognize the need to return to land, but the seawater has already reached a considerable depth in the tidal channel; and (**C**) aerial photograph taken during the low tidal level, depicting numerous tourists on the lower tidal flat. Indeed, the specified region has had numerous reports in recent years of tourists coming across dangers or having accidents, as documented in various instances [14; 15; 16]. In general, a lack of awareness of the potential dangers poses a pressing issue that demands effective monitoring and assessment strategies. From a coastal management perspective, recognizing the hazards linked to recreational activities on tidal flats is crucial. While installing warning signs along the coast offers a basic level of risk communication, this method may not be specific or engaging enough to effectively convey the dangers. Moreover, it fails to incorporate real-time updates reflecting the dynamic nature of beach environments. To address this, we propose an immersive solution designed to intuitively educate the public about these risks.