Nenana Ice Classic - Official Date and Time the River moved now Available

The movement of the tripod on the Tanana River  ice tripped the time clock on 2020-04-27 at  12:56:00

Timing everything from the vernal equinox given  this plot:

So this years data shows a continual decrease, year on year, from about 1964 onwards (on average!).

No thermometer juggling possible, no tree rings to bodge, no models to distrust. Is this a real indicator of AGW?