Field of view of the observations and magnetic field inferred from the inversions of the polarimetric map. Top panels: intensity in the wing (left panel) and core (right panel) of the Ca II 8542 Å line. The white square delimits the region in which the spectropolarimetric inversions were performed. Bottom panels: line-of-sight magnetic field (left panel) and magnetic field inclination (right panel). The white contours mark the boundary between the umbra and penumbra. The red, orange, and yellow contours delimit the regions in which 14, 7, and 3 umbral flash profiles, respectively, were detected during the 13 min of the temporal series that we analyzed.