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Following the planet-encircling dust event (PEDE) of Mars Year (MY) 34, MRO/HiRISE has seen many more candidate RSL than in typical Mars years. They were imaged at more than 285 unique locations from August 2018 to August 2019, 157 where RSL had not been seen previously. Of the locations where RSL had been observed in the same season of prior Mars years, 34 sites had more extensive RSL coverage than MY29-33; none had less extensive RSL. 150 active RSL sites were identified in the southern middle latitudes (SMLs) versus the 36/year average during MY28-33. RSL are present on ~87% of the HiRISE images covering steep, rocky slopes in the SML in southern summer of MY34, rather than ~40% as in prior years. Post-PEDE RSL are also present over a wider combined range of latitude, slope aspect, and season than in prior years. These RSL sites usually show evidence for recent dust deposition. There are clear dust devil tracks in 54% of post-PEDE images with RSL, and in 73% of such images in the SMLs and L=236°-360° (late southern spring to the end of summer), where and when dust devils are most active. The tracks indicate dust lifting, by several mechanisms. We suggest that dust lifting processes on steep slopes may initiate and sustain RSL formed from flows of dust (perhaps clumped) and/or sand that is destabilized by dust movement. The otherwise puzzling recurrence and year-to-year variability of RSL activity can be at least partly explained by variable yearly dust fallout.