Lost archaeological remains have become visible in grasslands and crops across Wales after prolonged hot and dry weather, BBC News reports.
Wales has recorded about 5% of its average July rainfall following repeated heatwaves and a drier than usual period from April to June. Drought has also been declared in parts of the country.
Experts said the conditions have exposed a range of buried features, including Roman buildings and First World War practice trenches. Many can only be seen from the air as distinctive cropmarks or parchmarks, and some have not been visible for “two or three decades”, according to the Royal Commission on the Ancient and Historical Monuments of Wales.
The marks form when vegetation grows differently over buried archaeological features, such as old ditches that retain water and nutrients. They can fade quickly once the weather changes.
Archaeologist Dr Toby Driver has been recording the sites from the air. He said archaeologists previously expected to wait five to seven years for a major heatwave summer suitable for aerial archaeology, but such summers are now occurring “every year”.
The Royal Commission said east and north-east Wales had been very dry since mid-May, while much of west and south Wales had stayed relatively damp and green until late June heatwaves scorched grasslands more widely.
Photographs released by the national archive for the Welsh historic environment followed flights from Haverfordwest and Caernarfon airports in June and July. Dr Driver said windy conditions had made some longer flights difficult, while in very dry areas some cropmarks were faint and required digital image processing to make hidden details clearer.
Among the discoveries or newly visible details are a rectangular Neolithic long barrow at Welshpool, Powys, dating back about 5,000 years, and buried Roman buildings at Caerhun Roman fort in Conwy.
Parchmarks of First World War practice trenches have also been seen beneath a golf course at Deganwy, Conwy. Near Llandysul in south Ceredigion, a previously unrecorded Iron Age or Romano-British double-ditched farmstead was revealed in ripening cropmarks.
