Surprising performance of a 28 MHz vertical antenna while lying on the ground

Just a quick post. As a storm passed over Ireland this afternoon, I dropped my vertical antenna for 28 MHz to protect it from the high winds. Normally the half-wave vertical sits about 4.5 metres above ground level and is reasonably clear in most directions.

I noticed that while it was lying horizontal on the ground, I was still receiving WSPR signals on 28 MHz!

I propped up the antenna so that it was lying horizontal and about 30cms above the ground. After 4-hours of listening, I heard 52 stations on WSPR on 28 MHz and these are shown above.

It's just surprising to see signals coming in from North America on 28 MHz on an antenna that almost on the ground and I literally have to step over.