iPhone 6 Plus Screen Hazy Grey, Unresponsive

Recently upgraded to iOS 8.2. Had 2 episodes today where I received:

1.) A text message and

2.) a phone call, where... In each case the screen was hazy (grey) with static.

I could not get the screen to respond with a swipe, so had to press the power button twice to restore the display and allow it to work. Any ideas? Software/ Hardware? I know it's hard to say...