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Here we present the study of a compact emission source during an X1.3 flareon 2022-March-30. Within a $\sim41$~s period (17:34:48 UT to 17:35:29 UT), IRISobservations show spectral lines of Mg II, C II and Si IV with extremelybroadened, asymmetric red-wings. This source of interest (SOI) is compact,$\sim$ 1\arcsec.6, and is located in the wake of a passing ribbon. Two methodswere applied to measure the Doppler velocities associated with these red wings:spectral moments and multi-Gaussian fits. The spectral moments method considersthe averaged shift of the lines, which are 85 km s$^{-1}$, 125 km s$^{-1}$ and115 km s$^{-1}$ for the Mg II, C II and Si IV lines respectively. The red-mostGaussian fit suggests a Doppler velocity up to $\sim$160 km s$^{-1}$ in all ofthe three lines. Downward mass motions with such high speeds are very atypical,with most chromospheric downflows in flares on the order 10-100 km s$^{-1}$.Furthermore, EUV emission is strong within flaring loops connecting two flareribbons located mainly to the east of the central flare region. The EUV loopsthat connect the SOI and its counterpart source in the opposite field are muchless brightened, indicating that the density and/or temperature iscomparatively low. These observations suggest a very fast downflowing plasma intransition region and upper chromosphere, that decelerates rapidly since thereis no equivalently strong shift of the O I chromospheric lines. This unusualobservation presents a challenge that models of the solar atmosphere's responseto flares must be able to explain.

Extreme Red-wing Enhancements of UV Lines During the 2022 March 30 X1.3 Solar Flare