Selected IRIS spectra and AIA intensities for the first flare. The vertical dashed lines in the AIA images are the positions of the IRIS slits. The numbers on the IRIS images show the positions of the selected points in Fig. 14. The +’s and ×’s in the AIA images indicate the positions of these points in the AIA images. Underneath are the IRIS spectra (solid black line) and their fits (black dashed line) for the selected positions. The green solid line is the background, the blue dashed line is background + Fe xxi line, while the vertical line is the rest wavelengths of the Fe xxi line.