<p>Snow avalanches are major natural hazards in snow-covered mountainous areas, with high velocities and huge impact pressures that pose a serious threat to infrastructure and human life. The nature of pressure fluctuation in snow avalanches may amplify the impact pressure significantly, and the fact that real avalanches usually move on erodible bed may affect the assessment of avalanche impact pressures. Numerous studies have investigated the impact behavior of snow avalanches by field observation or experiments. However, the phenomenon of pressure fluctuations in avalanches is rarely discussed in existing studies, and few studies have linked erosion with snow avalanche impact behavior so far. In this study, we investigate the temporal evolution characteristics and influence factors of avalanche impact pressures through small-scale experiments using real snow, aiming to explore the pressure fluctuation and the effect of erosion behavior on the impact pressure. The results show that the Froude number obtained from these experiments agree with real avalanches, and the impact signals obtained from the experiments are similar to those of real avalanches, indicating that small-scale experiments can effectively capture the impact behavior of avalanches. Regular fluctuations of impact pressure are obtained, which could be associated to the internal inhomogeneity of snow avalanche. These pressure fluctuations are found to be velocity-dependent and correlated with the impact pressure. Interestingly, on a temporal scale within a single avalanche, the maximum fluctuation does not occur at the moment of maximum impact pressure, indicating the relatively stable internal structure at the maximum pressure. In addition, it is found that the erosion process has a complex influence on the impact behavior. Although the thickness of the erodible layer is not directly related to the impact pressure, it can change the movement behavior of the incoming flow, thus affecting the dominant role of inertia in the impact pressure.</p>