Gallage et al. (2021) describe interesting work in which 320 sand slopes were constructed in a 9m long and 1m deep glass sided sloping tank (flume) and then brought to failure by artificial rainfall at 100mm/h. Pore pressure sensors, LVDTs and Amplitude Domain Reflectometry (ADR) probes were used to monitor water movements in the sand and consequent slope movements. Digital cameras were used to record the slope movements. Failure in the form of a rapid flow slide was observed 75 minutes after the start of rain, with the period of rapid movement lasting approximately 5 seconds.