Drought in Wales reveals vast archaeological remains, a boon for aerial archaeologists

Wales is experiencing an unprecedented archaeological discovery boom, thanks to a prolonged period of warm and dry weather. The country has seen minimal rainfall, leading to the emergence of long-hidden historical sites across its landscapes.

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We would normally have to wait for every five to seven years for a record-breaking hot summer for 'aerial archaeology', but it is now happening every year.

These dry conditions have brought to light a variety of archaeological remains, from prehistoric burial mounds and Roman structures to World War I training trenches. Many of these are only visible from the air, appearing as distinct marks in crops and grass. Experts from the Royal Commission on the Ancient and Historical Monuments of Wales (RCAHMW) note that some of these sites have not been visible for two to three decades.

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This year it has been quite windy across Wales, so some of the longer flights for recording crop marks have been challenging to fly.

The phenomenon occurs as vegetation draws on better nutrients and water reserves trapped in ancient, long-vanished earthworks. This results in lush green growth that clearly stands out from the surrounding drier vegetation. However, these ephemeral traces can disappear as quickly as they emerge once weather conditions change.

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Sometimes the crop marks are so clear that they just jump out as we circle the aircraft around them to photograph them.

Archaeologist Dr. Toby Driver described the current situation as a boon for "aerial archaeology," noting that what used to be a rare event, requiring a "record-breaking hot summer," is now happening annually. He highlighted that while some areas of Wales remained wet, others experienced severe dryness, revealing a wealth of history. The RCAHMW has released striking aerial photographs of these discoveries, captured during flights over the past few months, showcasing everything from Neolithic long barrows to Iron Age farms.

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In those cases, we digitally rebalance the colour bands on the image, and the archaeology really 'pops out and reveals previously hidden detail – these images appear as black and white.