Ngamahu, Flame's Advance ascendancy node. How can I see the damage buff?

Hi,
Ngamahu, Flame's Advance gives 70% damage bonus every 10 seconds for 3 seconds. Is there any way to see when that happens ? I use vaal ground slam and using the vaal skill at the right moment (when the 70% bonus is received) makes a big difference. I didn't notice any effect on the character, or anything on the top left that shows the buff (only way I know the buff is happening is by hovering my mouse on the tooltip and I can see the dps go up for 3 seconds)

Thanks!