The market may not have a tock, but it has a tick, a $TICK reading to be precise. Extreme tick readings do not occur all that often, but when they do they are notable mainly because they often indicate either selling or buying exhaustion. While not necessarily an imminent turn signal the recent past shows a pretty powerful trend change signal that one should at least pay attention to:
In short: A tradable low may not be too far off into the future. Tock.