Encara no tenim significats per a "big thunderhead".
1A big thunderhead passed over, and I breathed shade, grateful.
2Big thunderheads far out to sea.
3Big thunderheads were piling up in the west when we got out on the highway and the sun was just going down behind them.
4I looked at the sky, but all I could see was a pair of big thunderheads rising up like soapsuds behind the Muckleroy house.