The CT DEEP is citing cold-shock that in terms of research not much is known about.
http://www.fecpl.ca/wp-content/uploa...-etal-2008.pdf The CT DOT will pretreat roads up to 5 days in advance of a storm, of which we had two before all of the rain fell. Most pretreatment happens on bridges and other dangerous areas. The Calcium-chloride used does not activate until water hits it. It is also said that it has little effect on fish but that statement is by the manufacturers of the product.
What I know from the few times I've fished for holdovers is that these fish ball up like chordwood so much so that a jig hits multiple fish on a drop. So it is likely that this fish kill occurred in one or a few specific areas, then the tides moved the fish to their final resting places. I don't like the cold-shock answer either due to water's ability to hold the same temperature, the fact that SB tend to favor areas of warm water discharge especially in cold months. However, the study also noted that certain very cold temperatures reduces a fishes "fight or flight" response and could actually send them swimming in the wrong direction. The only thing I disagree with the DEEP on here is that a simple speculation answer of "it's cold-shock" without any proof of analysis from the dead fish.