This! The compaction was quick. One hour into the heavy sleet I had lost about .5 inches of snow depth. Depending on when/if they cleared their board can easily explain the lower than expected report. Also if you really examined the sleet, I did of course because I (aren’t we all) am a weather nerd, it was watery and was very diverse in size, which was surprising to me. Smallish sleet pellets seemed to dominate, at least in my yard. I am about 13 miles due south of DCA, just about on the river so similar, except we have trees instead of concrete. My final tally was 8.5”, but I cleared my measuring area soon after the sleet started and then every 6 hours ish