What if they expend all the fuel straight up and plunge straight down, eh?
You have heard of the "solar wind". This wind increases in force during solar flares and coronal mass ejections. Hell the solar wind speed last night was up to over 1000 km/sec.
Also the height of the atmosphere increases during magnetic storms, and increases atmospheric drag, which can drag down those satellites. It's like the tornado at the start of Wizard of Oz!