The prolonged spell of hot, dry weather across Wales has revealed a remarkable array of buried archaeological sites, with ancient monuments emerging in fields and grasslands as distinctive cropmarks and parchmarks.
Following an exceptionally dry period between April and July, aerial archaeologists from the Royal Commission on the Ancient and Historical Monuments of Wales (RCAHMW) have been taking to the skies to capture these fleeting discoveries before changing weather conditions cause them to disappear once again.
While eastern and north-eastern Wales experienced dry conditions from mid-May, much of the west and south remained green until a series of late June heatwaves scorched the landscape. The intense conditions exposed a wide variety of hidden archaeological features, including prehistoric long barrows, Iron Age forts, Roman buildings and even First World War practice trenches.
Many of the sites have been recorded previously, but several have not appeared so clearly from the air for more than 20 to 30 years. Others are entirely new discoveries, offering valuable insights into Wales' rich archaeological heritage.
Dr Toby Driver, the Royal Commission's aerial archaeologist, said the increasingly frequent heatwaves are transforming the way archaeological surveys are carried out.
"We used to wait five to seven years for a record heatwave summer for aerial archaeology, but now they come around every other year," he said. "This year has also been particularly windy across Wales, making some of the longer survey flights especially challenging."
Dr Driver explained that while some archaeological features are immediately visible from the aircraft, others require specialist image processing to reveal their full extent.
"Sometimes the cropmarks are so clear they jump out as we orbit the aircraft to photograph them. In other areas, where the ground is extremely dry, the marks can be very faint. By digitally rebalancing the colour bands of the images, we can make the archaeology really 'pop', revealing details that would otherwise remain hidden."
Working alongside pilots from FlyWales, Haverfordwest, and Caernarfon Airport, the Royal Commission has been conducting aerial surveys across the country throughout the summer. The information gathered is being shared with Cadw and regional archaeological teams to help protect and better understand Wales' historic environment.
The aerial surveys have also supported National Park authorities by documenting areas affected by recent wildfires, providing valuable records of environmental damage alongside archaeological discoveries.
All photographs taken during the surveys will be preserved within the National Monuments Record of Wales, ensuring they remain available for researchers and the public for generations to come.
Highlights from this summer's discoveries include:
- A spectacular Neolithic long barrow near Welshpool, dating back around 5,000 years, displaying its clearest cropmarks in three decades.
- Newly revealed details of buried Roman buildings within the Roman fort at Caerhun (Canovium), Conwy.
- A previously unknown Iron Age or Romano-British double-ditched farmstead near Llandysul in Ceredigion.
- First World War practice trenches uncovered beneath a golf course at Deganwy, Conwy.
- A vast Iron Age concentric enclosure near Lampeter, measuring approximately 170 metres across and believed to have been used as a cattle corral around 2,000 years ago.
As climate patterns continue to produce hotter, drier summers, these brief windows of visibility are becoming increasingly important for archaeologists. While drought poses significant environmental challenges, it is also providing rare opportunities to uncover traces of Wales' past that have remained hidden beneath the landscape for centuries.
Sources : Royal Commission on the Ancient and Historical Monuments of Wales