Most of the automated tracking tools, with except Algoroo, really showed very huge spikes in google algo update in this whole year (2017) and volatility on either Tuesday or Wednesday, May 16th or 17th, of this week.
MozCast is a weather report showing turbulence in the Google algorithm over the previous day (or see the 5-day history on the left). The hotter and stormier the weather, the more Google's rankings changed.
It is a robust search engine rank monitoring platform with a full featured API, built specifically for SEO agencies with bulk keyword tracking needs. really showed very huge spikes in google algorithm update.
Algoroo is a Google algorithm tracking tool developed by DEJAN . this system monitors roughly 17,000 keywords to 100 search positions deep and looks for fluctuations. but exception of algoroo other tools showed bigger spikes.
In this case, the tools went insane and there was very little SEO chatter. It might be Google UI changes or something else but I am not sure.