OK, now that's weird

[Zanovar]

just heavy plants probably

 

[runzwithsizorz]

Was it windy? Wind could have blown that umbrella pole around enough to put enough pressure on the glass to shatter it.

The umbrella separates from that pole, and I store it inside when not in use.

 

[MrDudeMan]

The screwdriver could have become airborne when the glass shattered. If it also gained angular momentum, I would have no trouble believing it could stick in the deck. Relative to the deck surface, an orthogonal resting place is somewhat unlikely with a high angular spin, but it's certainly not impossible.

 

[FeuerFrei]

One of dem potses smote the falling screwdriver, which was handle-up at the time, causing tippy tip to penetrate dat dere deck.