The direct measurement of the particle egress rate and heat losses from a particle receiver has been a topic of interest for the advancement of CSP technologies. Particle-plumes that egress from the receiver’s cavity have variable size, density, and rate of egress, which can be a challenge for the field of thermometry. In a previous publication, a methodology to estimate the average particle temperature and discharge rate of a particle curtain was developed by the University of New Mexico (UNM)-Sandia team. This work focuses on the application of a novel non-intrusive method using a high-speed IR camera (ImageI8300 from Infratec) and a visible-light camera (Nikon D3500) to achieve the estimation of the particle egress rate as well as the corresponding advective losses of the particle-plume during on-sun tests at Sandia. Data sets were collected for multiple test days with different test conditions throughout the test campaign. To understand which variables impact the particle egress rate of the receiver, a correlation analysis was completed to determine the impact of 6 variables which include: average particle temperature, curtain mass flow rate, input heat flux, wind speed and direction, and receiver flow configuration. From the results, it was determined that the average particle temperature as well wind direction have a positive correlation to increased particle losses from the system.