I don't think there is an easy way unfortunately. In the CLI through "show log buf | inc channel" then you'd see what channel it was on and what it's gone to e.g.:
kernel: Radar found on channel 140 (5700 MHz)
ah_dcd: One or more parameters for the access radio wifi1 changed. Its current channel is <124>, Tx power is <6*> dB, beacon interval is <100> TU, and EIRP is <15.77> dBm, reason: 4.
Would be nice to have in the GUI though!
All APs at this site are now running with DFS channels available. Different types of pings make sense. I hadn't thought of that. Thanks for the help as I figure this out.
One last question would be if there's anyway to see what channel the AP changed from, as the notification mentioned above only says what channel the AP changed to. I'm just trying to figure out what info I have available as I monitor and evaluate the impact of using DFS channels.