Firstly this could have ended bad, as it turned out it was a very cheap lesson for me, I had a plenty of time to act early and did nothing.
Anchored at the sand hills on Moreton Isl in a northerly in about 5mts of water, 30mtrs of chain out. A storm was predicted hours before it came through around 8.00pm . 180 degree windshift and increase from 10knts up 30knts and suddenly I was in 2.5 mtrs of water with a lee shore right behind me. I had the engine running and all systems on in case the anchored dragged.
Fortunately the rocna mk2 reset instantly and held us so all was well. I should have moved the boat offshore to allow more room for when the inevitable windshift came as the storm was coming up from the south. A cheap lesson.
Below is the track from the anchor alarm, the long light blue is the windshift and we covered the distance in probably not much more than a minute. I don't know how much room we had behind us but based on the depth it wasn't much. Happy I invested in an oversize anchor.