Is there a data base for the dates of the polar vortex reversals since record keeping began I think it said 1979?  I am curious if there was a similar one to this one in progress in 2017?  I read on www.SpaceWeather.com  site that the current one is the strongest since record keeping began? 
Thank You.
I am a volunteer spotter with the US Weather Service in Portland Oregon.
So all this kind of activity really interests me.